Ink on the Mind: A Guide to Psionic Tattoos

[Garryl]

Ink on the Mind: A Guide to Psionic Tattoos
Psionics is fun! It's like magic, but different, and in a good way. Not just mechanically, but also thematically, which builds back into the mechanical differences in some of the peripheral material, too.

One of those thematic-mechanical difference things is with psionic tattoos. They're the psionic equivalent of potions, for the most part. Most of the same logic and wisdom about potions applies to psionic tattoos. However, they have some rather nice differences that make them better than potions off the bat (ignoring, for the moment, the fact that magic has a lot more support than psionics so there are just more options for bottled spells than inked powers).

This guide isn't about explaining or even necessarily summarizing all of the rules around tattoos, just the important parts you need to use them in a game and some of the more interesting tidbits that are easy to overlook. As with all guide, consult the source material for actual rules text.

Psionic Tattoos
Psionic tattoos are kind of like the psionic equivalent of potions. They're not really the same, but they fill the same basic conceptual niche and it's an easy comparison to make. Tattoos store the effect of a low-level power and can be activated at a later time to use said power.

Psionic tattoos are, as the name implies, tattoos. They are psionically charged ink in your skin. The design of a tattoo is fixed, but its location isn't (you can move one about your body as a standard action). You can even transfer a psionic tattoo to or from another willing (or dead/unconscious) creature. You have to touch a tattoo to activate it, so you'll usually want to leave most of your tattoos on visible, or at least accessible, areas of your body. You don't need any special skill or training to activate a psionic tattoo, even if you don't know what it does. You don't even need to be psionic.

Activating a psionic tattoo (referred to as "tapping" the tattoo) is a standard action. This provokes an AoO. If you're hit, you need to make a Concentration check (DC 10 + damage dealt, or DC 20 if grappled), otherwise your action is wasted and the tattoo doesn't activate (the tattoo itself doesn't get damaged or lost or anything, and you can still activate it again with your subsequent actions). When successfully activated, a psionic tattoo produces the effect of its power and fades away.

The wearer of the tattoo counts as both the power's manifester and its target.

Any decisions for the tattoo's power are made by the creator when the tattoo is scribed. This includes things like what energy type the power manifests with, which augmentation options are selected (for tattoos above the minimum manifester level for the power), and so forth.

A psionic tattoo costs 50 gp times its power level times its manifester level. Like with potions, add 5 gp to the market price for every 1 xp the power costs to manifest (no need to worry about expensive foci or material components as powers don't have those). Crafting a psionic tattoo requires the Scribe Tattoo feat (itself requiring manifester level 3rd) and the ability to manifest the desired power at the desired manifester level. Tattoos can store the effect of any 3rd-level or lower power that targets one or more creatures.

An important thing that's easy to overlook is that psionic tattoos can be made at any manifester level, just like with potions. The psionic tattoo entry in the SRD only talks about making tattoos at the minimum manifester level (and likewise its tables only show those prices), but the Scribe Tattoo feat says otherwise and gives the general price structure, and the psionic items basics section specifically calls out psionic tattoos as among those items that can be above the minimum ML for the power and references the standard magic item creation prices for psionic items (which Scribe Tattoo's formula follows).

If you come across an unidentified tattoo, you can identify it with a DC 25 Psicraft check (takes 1 minute, no retry). If you're wearing it, you can also concentrate on it and make a DC 13 Intelligence check to get some hint as to its effect. As always, an identify spell or power can tell you exactly what the story is, if need be.

Potions vs. Tattoos
First off, the similarities. Both potions and tattoos are single-use items that hold an effect of 3rd-level or lower that targets one or more creatures, they both can be used by anyone, no matter how magical, psionic, or mundane they are, they both require a standard action and provoke an AoO to use, they both target and count as being manifested or cast by the user, and they both use the same overpriced pricing scheme (50 gp x effect level x CL or ML). Any decisions for the effects produced by a tattoo or potion are made when the item is created, not used. Incorporeal creatures can't use tattoos or potions (albeit for different reasons). Tattoos and potions both generally require a free hand to use (potions to hold, unstopper, and drink, tattoos to actually touch the tattoo).

Tattoos have a few advantages over potions. They're inked on the skin, so they needn't be drawn (usually a move action that provokes AoOs), and you can't be sundered or disarmed of them. The restrictions on which powers can be stored in a tattoo are less restrictive than those for spells in a potion. Potions are limited to non-personal spells with a casting time of under 1 minute. By contrast, personal powers and powers with longer manifesting times can be made into tattoos.

Tattoos aren't strictly better than potions. You can only have 20 tattoos on your body at once (any more and they all trigger immediately). Tattoos have to be inked onto an actual creature, so they're harder to store for sale and to transfer via mail or courier, for example, especially en masse. Transferring them from one creature to another is a standard action, which also makes it slightly less convenient to use on an unconscious ally (a standard action to transfer plus a full-round action to activate vs. a potion's move action to draw and full-round action to pour). Potions also have a variation, oils, which are designed for use on objects, while tattoos have no such object-based equivalent.

Here's a summary of most of the similarities and differences.

	Potions	Psionic Tattoos
Uses	Single-use	Single-use
Maximum Effect Level	3rd-level or lower spells	3rd-level or lower powers
Effect Target Limit	Non-personal, one or more creatures (or objects for oils)	One or more creatures
Effect Activation Time Limit	Casting time less than 1 minute	No manifesting time restrictions
Effect Decision Making	Decisions made beforehand by creator	Decisions made beforehand by creator
Activation Target	Imbiber	Wearer
Activation Action	Standard action (imbibe potion, provokes AoO, Concentration check if struck)	Standard action (touch tattoo, provokes AoO, Concentration check if struck)
Activation on Unconscious Ally	Full-round action (pour potion down throat, AoO as above)	Full-round action (touch ally's tattoo, AoO as above)
Must be Drawn?	Yes (move action to draw if not already held, provokes AoO)	No
Sunderable?	Yes	No
Disarmable?	Yes	No
User Requirement	Corporeal	Creature have a permanent surface on which to inscribe the tattoo
Carry Limit	Limited by carrying capacity only	Maximum 20 tattoos
Transferrable?	Yes (object)	Yes (standard action, by touch, willing or unconscious/dead creature only)
Identification	DC 25 Spellcraft check, or by taste/texture/etc.	DC 25 Psicraft check, or DC 13 Intelligence check to get a hint
Market Price	50 gp x spell level x CL (plus special components costs)	50 gp x power level x ML (plus special components costs)

Potions (and magic in general) have a lot more support material than psionic tattoos. In addition to the sheer volume of spells printed over dozens of source books that can be placed in potions, there are many feats, items, classes, and spells specifically designed to enhance the use of potions that psionic tattoos don't have access to.

Crawling Tattoos
Crawling tattoos are universal items (made with the Craft Universal Item feat, not Scribe Tattoo) that are similar to regular old psionic tattoos. The main difference is that instead of just producing a power's effect when tapped, a crawling tattoo gets up off your body, crawls over to a target of your choice, and touches the target to apply the power directly. They move reasonably quickly (30 ft. move speed), and can be sent off towards anyone within line or sight (no range limit). They have a neat advantage of being able to apply area powers and to deny the target a Reflex save (Fort and Will saves are still valid, however). You can also have them crawl over to distant allies to apply beneficial powers. Unfortunately, crawling tattoos can be attacked and destroyed (AC 18, 10 hp, hardness 5), and as fine creatures, they need to move into their target's space to attack, provoking at least one AoO from the intended target and probably anyone else in melee. Read up on them if you're interested, but crawling tattoos aren't the focus of this guide.

It's worth noting that crawling tattoos can be used to apply powers such as metaphysical weapon to objects, which psionic tattoos otherwise can't do (objects aren't creatures and thus can't have psionic tattoos on them).

Why to Use or not Use Psionic Tattoos
Psionic tattoos have the same general issues that potions do without supporting material. They are expensive (twice as much as a power stone, ~3.3 times as much as a charge from a dorje) and risk an AoO. They're a lot more usable than potions, which also need to be drawn (a move action) and are easily breakable, but the fact remains that the high price makes tattoos uneconomical under normal circumstances. Like with potions, common character optimization wisdom says that you shouldn't usually use psionic tattoos. If your character is a manifester, dorjes are by far superior for frequently used powers (30% of the price per use, no AoO), and power stones are better for infrequent ones (half the price, augmentable with your own PP if desired). For non-manifesters, psionic tattoos offer access to the occasional power, but simple economics makes 2nd- and 3rd-level powers too expensive to be worthwhile over more permanent gear upgrades. Some consumable use is acceptable, but not too much. The DMG seems to assume approximately 10% of wealth gained from encounters is lost to resale markups and consumable use (average wealth gain from encounters at a given level is approximately 10% higher than the difference in wealth by level from that level to the next).

That being said, supporting material can make psionic tattoos rather impressive. It's unfortunate that the main source of said supporting material, special psionic tattoos, is unupdated 3.0 edition content (and psionics is notorious for not taking as well to 3.0e-to-3.5e conversion as other material), but said material skirts at the edges of the components that are hard to convert, making the vast majority of it directly convertible. See the next post for more details.


References

• Psionic Tattoos
  
• Concentration
  
• Scribe Tattoo: You can create a psionic tattoo of any power of 3rd level or lower that you know and that targets one or more creatures.
  
• Psionic Item Basics - Descriptions: Increasing the manifester level so increases the cost of the item; see Table: Estimating Magic Item Gold Piece Values, substituting “spell” for “power” and “caster level” for “manifester level” as appropriate.
  
• Psionic Item Basics - Manifester Level: For psionic tattoos, power stones, and dorjes, the creator can set the manifester level of an item at any number high enough to manifest the stored power and not higher than her own manifester level.
  
• Potions and Oils
  
• Creating Potions: Spells with a range of personal cannot be made into potions.
  
• Brew Potions: You can create a potion of any 3rd-level or lower spell that you know and that targets one or more creatures.
  
• Crawling Tattoos
  

Change Log

(click to show/hide)

20/6/2017: Reposted to Min Max Forum. The link to the old discussion thread on Min Max Boards is defunct now.
1/1/2016: Happy new year! Fixed some incorrect information about tattoo targeting. Like potions, they only target the wearer.
30/12/2015: First posted.

[Garryl]

Getting Wired: Unofficial Conversion
The Mind's Eye: Getting Wired is a wonderful web article detailing a number of new psionic items and powers dealing with psionic tattoos. It just has the slight misfortune of being published under 3.0 edition Dungeons and Dragons rules and not having been officially updated to 3.5 edition. As such, I would like to stress that what I am presenting here is an unofficial conversion, so run it by your DM first before using it.

(click to show/hide)

Here is my take on the material that needs to be converted. The rest of it should work just fine with no changes at all.

Psionic Tattoo Mastery [Item Creation]
Prerequisite: Scribe Tattoo.
Benefit: You can create a psionic tattoo of any appropriate psionic power of up to 9th level. The amount of time required to create a psionic tattoo is one day per 1,000 gp of base cost of the tattoo. Tattoos of powers higher than 3rd level are larger and more intricate; these tattoos count as 2 more tattoos per power level above 3rd (note that the normal limit you can have is twenty tattoos).

You can also create tattoos of powers enhanced with metapsionic feats. You must have each metapsionic feat you apply on your list of feats. The psionic tattoo has an effective metapsionic level 1 level higher than the power's level for every 2 points the metapsionic feats increase the power's cost, plus 1 level for each metapsionic feat whose use normally requires the manifester to expend her psionic focus. The metapsionic level is used for calculating the base cost and the number of slots used by the metapsionic-enhanced tattoo only. Metapsionic-enhanced tattoos are limited by your manifester level, and thus the number of power points you can spend at once, as normal.

Additionally, you can create special psionic tattoos.
Normal: You can create psionic tattoos of up to 3rd-level powers, but not with metapsionic feats applied.
Note: In a campaign with a lot of psionics or one where psionic tattoos are commonplace, you may want to simply replace the Scribe Tattoo feat with the Psionic Tattoo Mastery feat.

Basic Tattoos

• Fuse: Triggers and recovers at the new tattoo limit of 20, not 17.
• Mental Tap: The tattoo is activated as a swift action (clarification).
• Amplifier: The maximum number of power points you can spend to amplify the tattoo is equal to your normal limit on power points spent (your manifester level) minus the normal cost of the power. The concept of a metapsionic cap was removed in the new edition.

Advanced Tattoos

• Transmitter/Receiver: Removed. The concept of psionic attack and defense modes were removed in the new edition.

Psionic Tattoo Mastery
Getting Wired introduced the Psionic Tattoo Mastery item creation feat. The benefits of this feat are threefold.

• First, it allows one to create psionic tattoos of up to 9th-level powers, up from 3rd.
• Second, it allows one to create psionic tattoos enhanced with metapsionic feats (such as Extend Power and Maximize Power).
• Finally, it is a prerequisite for the creation of the special tattoos described in the article.

The nature of this feat is such that it alters what items are available at large, even if you do not take the feat yourself. Simply by having it in the campaign world, psionic tattoos of 4th- through 9th-level theoretically become available for purchase, as do metapsionically-enhanced tattoos. This alone is a significant departure from the normal limitations of psionic tattoos.

Higher Level Psionic Tattoos
Higher level tattoos require more slots than normal. While 1st- through 3rd-level powers still use only one tattoo slot, every power level above 3rd increases the number of slots used by 2 (3 slots for a 4th-level power, 5 slots for 5th-level, and so on, up to 13 slots for a 9th-level power). While you can carry many low-level powers, higher-level powers quickly run up against the 20 psionic tattoo limit.

Power Level	Minimum ML	Tattoo Slots	Price (at minimum ML)
1st	1	1	50 gp
2nd	3	1	300 gp
3rd	5	1	750 gp
4th	7	3	1400 gp
5th	9	5	2250 gp
6th	11	7	3300 gp
7th	13	9	4550 gp
8th	15	11	6000 gp
9th	17	13	7650 gp

Using high-level psionic tattoos as consumables is prohibitively expensive. Using the occasional one for a power on demand can be worthwhile under the right circumstances, however. The very fact that it enables otherwise mundane characters to use high level psionic powers is a bit of a game changer. Combining them with the special tattoos described in the Getting Wired article to preserve said psionic tattoos and make them reusable, however, can add some significant utility to otherwise mundane characters.

Special Psionic Tattoos
Getting Wired introduced a number of special psionic tattoos. They are divided into basic tattoos, which interact with other psionic tattoos, and advanced tattoos, which have unique effects of their own.

Basic tattoos modify and interact with other tattoos. They have a variety of useful and unique effects, from lowly fuses, which protect your psionic tattoos from discharging if you have more than the 20 tattoo limit, to mental taps, which allow you to activate psionic tattoos as a purely mental swift action.

Unlike psionic tattoos, basic tattoos cannot be transferred from creature to creature. If moved off your body, a basic tattoo fades away, like a used psionic tattoo. Also unlike psionic tattoos, only a few basic tattoos are single-use, the majority being usable any number of times without fading.

Basic Tattoo	Links	Tattoo Slots	Price	Notes
Fuse (F)	No	1/3	25 gp	Prevents tattoos from going off if you have too many.
Integrated Circuit (Ic)	No	1	50 gp	Lets you change the links of other tattoos.
Circuit Breaker (Cb)	No	1	300 gp	Protects against nullify tattoos and overload tattoos powers.
Relay (R)	Yes	1	50 gp	Links up to 3 psionic tattoos to trigger one after the other.
Mental Tap (Mt)	Yes	1	800 gp	Tap linked tattoo as a swift action.
Capacitor (C)	Yes	1	1250 gp	Linked tattoo is reusable, but capacitor must recharge.
Transducer (T)	Yes	1	1250 gp	Spend PP to recharge linked capacitor faster.
Amplifier (A)	Yes	1	1250 gp	Spend PP to empower linked tattoo.
Inducer (I)	Yes	3	2400 gp	Linked tattoo triggers automatically on a preset condition.
Advanced Tattoo	Links	Tattoo Slots	Price	Notes
Emitter (E)	Yes	11	8000 gp	Produces a prismatic spray-like effect around you.
Psychic Battery (B)	No	*	*	One-time pool of bonus PP.

• Non-linking Basic Tattoos: These basic tattoos provide a benefit as long as they are on your body.
  
  
  • Fuse (F): Triggers automatically to prevent your psionic tattoos from instantly going off if you have more than the maximum number of tattoos (20) on your body at once. Once triggered, the fuse fades and all of your other tattoos become nonfunctional until you get below the limit again. Fuses should never be necessary, as you can always control what tattoos you gain, but it may have a use in allowing you to store an excessive number of psionic tattoos on your body for someone else to use.
    
    25 gp market price, 1 tattoo slot per 3 fuses (rounded up).
    
    
  • Integrated Circuit (Ic): Normally, a tattoo's links are fixed once it is on your body. More links can be made to tattoos newly added to your body, but not with tattoos already there, nor can existing links be broken. This tattoo allows you to add or remove links between other tattoos. Adding or removing a link between two tattoos takes a standard action and costs 1 power point, so it's not something to be done in the heat of battle. Having an integrated circuit can be useful, and it's very cheap. Note: The text for the integrated circuit says that tattoos can link to it, but I can't think of any interpretation where its links influence its function, nor can I figure out how it linking would make sense with the way it's described.
    
    50 gp market price, 1 tattoo slot.
    
    
  • Circuit Breaker (Cb): This protects you from the nullify tattoos and overload tattoos powers introduced in the Getting Wired article. Instead of having your tattoos rendered inert for 1d4+1 minutes (nullify tattoos) or having them all go off at once (overload tattoos), the circuit breaker disables all of your tattoos until you spend a standard action and 3 power points to reset the circuit breaker. This tattoo is inexpensive, but is unlikely to be a good buy unless you expect your DM to throw one of those exact two powers at you.
    
    300 gp market price, 1 tattoo slot.
    
    
• Linking Basic Tattoos: These basic tattoos link to one or more other tattoos, providing benefits to them or altering their functionality. Tattoos that are linked together move around your body together as a unit. It's unclear, but presumably moving one linked tattoo off your body also requires moving the rest off as well. Since basic tattoos all fade when removed from your body, this is a bad thing. The only way to remove or change a link is for one of the tattoos to fade or to use an integrated circuit tattoo. Except for relays (which link to up to three psionic tattoos) and transducers (which link to a capacitor instead of a psionic tattoo), each linking basic tattoo can link to up to one psionic tattoo.
  
  
  • Relay (R): Up to 3 psionic tattoos can be linked to a single relay. All of the linked psionic tattoos get activated when you tap any one of them, although not immediately. The first one triggers at the end of the round in which the relay is activated, and one more triggers at the end of each round thereafter. The order in which the linked powers trigger is predetermined by the relay; which tattoo you tap makes no difference on the order. This lets you spend a single standard action to fire off multiple powers, much like the Linked Power metapsionic feat, but with fewer limits. Relays are also useful for letting capacitors and mental taps and other basic tattoos apply to multiple psionic tattoos instead of just one, as all of the psionic tattoos linked to a relay move together and link to others as a single psionic tattoo. Relays are very cheap and are extremely useful if you intend to make heavy use of psionic tattoos.
    
    50 gp market price, 1 tattoo slot.
    
    
  • Mental Tap (Mt): This allows you to activate a linked tattoo as a swift action instead of a standard action. It also becomes a purely mental action, allowing you to activate the tattoo even if you are paralyzed. Great for breaking the action economy, especially in conjunction with a relay, too.
    
    800 gp market price, 1 tattoo slot.
    
    
  • Capacitor (C): This basic tattoo essentially transforms the linked psionic tattoo (or tattoos, if linked via a Relay) from single-use items into rechargeable ones. Instead of the linked tattoo fading, the capacitor becomes drained. The capacitor recharges over the course of one day for every power point that the psionic tattoo's power would have used were it manifested normally, during which time you start each day with 1 fewer power point. Note that you don't actually need any power points for your capacitors to recharge automatically. Until the capacitor finishes charging, the linked psionic tattoo remains usable, but will fade as normal if tapped. This tattoo is probably what makes psionic tattoos so very appealing, even more so than mental tap's action economy shenanigans, as it changes tattoos from high-priced single-use effects to cheap repeatable effects.
    
    1250 gp market price, 1 tattoo slot.
    
    
  • Transducer (T): This tattoo attaches to a capacitor and lets you recharge it directly. You have to pay twice as many power points (2 power points spent for every 1 point the capacitor instantly recharges), but you can charge it up much faster, even in the heat of battle. You can also use leftover power points at the end of the day once you know you won't need them, for example.
    
    1250 gp market price, 1 tattoo slot.
    
    
  • Amplifier (A): This functions as a scalable Empower Power feat on a linked psionic tattoo by spending your own power points. The power is empowered by +25% per 2 power points spent, and you can spend no more than the difference between the power's normal power point cost and your manifester level (in other words, the amount of power points you'd be able to spend on metapsionic feats if you were manifesting it yourself). You must be a manifester (and be higher level than the psionic tattoo's manifester level) in order to get any benefit from this special tattoo.
    
    1250 gp market price, 1 tattoo slot.
    
    
  • Inducer (I): This applies contingency to a linked psionic tattoo, the trigger criteria being predetermined by the Inducer tattoo. This lets you do neat things like automatically revivifying yourself after death. Due to the existence of relays, you can use this to automatically trigger up to 3 powers, instead of the usual 1 power psionic contingency allows. Note that psionic tattoos linked to an inducer cannot be triggered normally, only by the inducer.
    
    2400 gp market price, 3 tattoo slots.
    
    
• Advanced Tattoos: Advanced tattoos have unique effects.
  
  
  • Emitter (E): An emitter essentially functions as a single-use prismatic spray-like effect, albeit in a burst around you instead of a cone and with a slightly different table for random effects. It can link with basic tattoos (other than amplifiers), and should be linked to a capacitor so as to be reusable (counts as an 8th-level power, so 15 day recharge without a transducer). It is very expensive, slot-wise, so your tattoo options will be very limited. Like basic tattoos, an emitter cannot be moved off your body without fading.
    
    8000 gp market price, 11 tattoo slots.
    
    
  • Psychic Battery (B): Functions as a single-use cognizance crystal, granting you a separate pool of power points to draw from once (any unused points are lost). You can't link a psychic battery to other basic tattoos, so there's no way to make it reusable. You're probably better off with a power stone (cheaper) or a cognizance crystal (more expensive but reusable), but strictly speaking, this does technically fill the "low-price, singular bonus use of one of your powers, not predetermined" niche. It's unlikely to be worth it when you consider what kind of fancy circuitry you could be hooking up with your psionic tattoos using the slots a high-capacity psychic battery would use, however. Anything above 7 power points really starts to eat into your tattoo slots. Like basic tattoos, a psychic battery can't be moved off your body without fading.
    
    Level equivalent is 1/2 the number of power points, rounded down. Market price is 500 gp plus the cost of a minimum manifester level psionic tattoo of the level equivalent. Tattoo slots is that of a psionic tattoo of the level equivalent (effectively equal to the number of power points minus 6).
    
    

Special Tattoos and Crawling Tattoos
Since crawling tattoos leave your body when you activate them, they don't play nice with special tattoos. At best, they just aren't effectively usable with capacitors (they fade when they deliver their power, not when they're activated, and they're not on your body at that time, anyways). At worst, they drag all of the special tattoos they're linked to off of your body, destroying them. If you want to use them together, double check with your DM what interpretation they're using, and maybe convince them to let crawling tattoos preserved by a capacitor come back to you once they've delivered their payload.


References

• The Mind's Eye: Getting Wired
  

Change Log

(click to show/hide)

20/6/2017: Reposted to Min Max Forum. Adjusted the wording on my take on a 3.5 update for the Psionic Tattoo Mastery feat.
1/1/2016: Happy new year! Fixed some typos and adjusted some formatting. Added a bit about crawling tattoos interacting with special tattoos.
31/12/2015: Formatting changes and clarification.
30/12/2015: First posted.

[Garryl]

Psionic Tattoo Builds and Tricks
Here are a number of miscellaneous tricks and character build snippets that may be helpful.

Cheap Tattoo Powers
Some powers can be acquired at lower level than you'd think.

• Psionic plane shift and psionic teleport are 3rd-level powers for Elocators instead of the usual 5th. Remember that in a tattoo, you only target yourself and all decisions (like where you're teleporting to) are made at the time of the tattoo's creation.
  

Extra Powers, Inefficiently
You can use psionic tattoos with a capacitor and a transducer to sort of get an extra power known. You can't change the ML or augmentation or other options once the tattoo is scribed, and the transducer's 2:1 inefficiency means you're paying twice as many PP as if you actually knew the power yourself. This is best for small non-augmentable utility powers that you know you're going to want but aren't worth spending a known power on, like call to mind, elfsight, float, skate, or synesthete. It's also good for accessing out-of-class powers that wouldn't even be an option for you, in which case it may even be worthwhile to invest in higher level powers and the dramatically higher PP cost they would have. A capacitor plus a transducer costs 2500 gp, so it's a bit expensive at lower levels. You can shave off the transducer (and 1250 gp cost) if you don't expect to want to use the power more than once every day or every few days.

Overleveled Powers
Psionic tattoos are cheap compared to permanent items. This can let you access normally-single-use powers above what you'd normally have access to at your level. With a capacitor (and a transducer, if you want to use it more than a couple times a month), you can have repeated access to such powers. A capacitor plus a transducer cost only 2500 gp combined to buy. Add in a mid- or high-level psionic tattoo, and you could be spending only around 8-10k gp for the ability to use, say, form of doom for 22 PP. Is form of doom worth spending 22 PP to manifest? At 16th level, when a Psychic Warrior would be able to learn it directly, probably not. At 8th level? Maybe.

XP-Free Powers
Since the xp cost of a power is paid when the tattoo is created (and factored into the market price, 5 gp per 1 xp), not when it's activated, you can repeatedly use tattoos of powers with xp costs without paying, assuming they're linked to a capacitor. Thus, things like psionic revivify, psychic reformation, and (for ultimate cheese) reality revision, which normally have prohibitively expensive xp costs to manifest, can be used repeatedly through psionic tattoos with only a one-time payment of xp (or gp, if buying them from another crafter).

Small-time use of this probably won't be a problem at most tables, but even a lenient DM will probably put their foot down on free reality revisions (even if the predetermined decision making means it's always the same wish).

If you find this to be an issue, I suggest the following unofficial fix to this likely-unintended loophole. Make capacitors also instantly drain xp equal to the xp cost of the power produced by a capacitor it preserves when the tattoo is tapped. If the user doesn't have enough xp to pay for it, the capacitor just doesn't preserve the tattoo (it fades as normal).

Spell-to-Power Tattoos
Spell-to-Power variant Erudites can learn psionic power versions of arcane spells. Theoretically, they can then make psionic tattoos of such converted spells.

Also, through various methods I don't know the details of but have seen discussed elsewhere, most any divine spell can be converted to an arcane spell, and thus to a power, and thus to a tattoo. In theory. Just make sure your DM's not in a book-throwing mood, okay?

Tattoo Circuit: Auto-Life

(click to show/hide)

This circuit has a market price of 8500 gp and uses 12 tattoo slots. When you die, this circuit automatically revives you (with revivify) at the end of the round, and then heals you for 1d12 hp the next round. The capacitor recharges after 12 days or 24 power points spent with the transducer.

You may wish to increase the manifester level on the Body Adjustment tattoo. For every +2 ML (+200 gp tattoo cost, +2 days capacitor recharge), it heals you for an additional 1d12 hp. Alternatively, you could replace it with one of the healing powers added in Complete Psionics.

You may also wish to add another psionic tattoo to the relay to provide some sort of protection after you've returned to life. The Vigor power is very inexpensive as a 1st-level power, effectively costing only 10 gp for every 1 temporary hp it provides. Its temporary hit points can also replace the immediate need for healing, as you would count as being at a positive hit point total and thus attain consciousness.

• Relay (50 gp, 1 slot)
• (End of 1st round) Psionic revivify (Egoist 5, ML 9, 3250 gp, 5 slots): Return to life with -1 hp as raise dead, no level loss, if you have been dead for no longer than 1 round.
  
• (End of 2nd round) Body adjustment (Psychic Warrior 2, ML 3, 300 gp, 1 slot): Heal 1d12 hp.
  
• (End of 3rd round) No psionic tattoo
• Capacitor (1250 gp, 1 slot)
• Transducer (1250 gp, 1 slot)
• Inducer (2400 gp, 3 slots): Activates when user dies.

Circuit diagram and tattoo links:

(click to show/hide)

Relay
|
(1) psionic revivify (2) body adjustment (3) (Empty)	—	Inducer
|
Capacitor	—	Transducer

References

• Erudite - Convert Spell to Power
  

Change Log

(click to show/hide)

20/6/2017: Reposted to Min Max Forum.
10/1/2016: Revised and clarified the section on xp-free powers.
6/1/2016: Added a section on using tattoos for extra powers "known" and for overleveled powers.
1/1/2016: Happy new year! Added a visual aid diagram for the auto-life tattoo circuit.
31/12/2015: Added XP-Free Powers tip. Added spell to power Erudite reference.
30/12/2015: First posted.