
As I explained on my simming tumblr, I've created an action that makes the process of applying hair textures a bit easier (or at least for me). I've shared the action I use below, and a tutorial in case you would like to make your own. :)
Using the action is very simple; simply download, extract, and load the action in Photoshop. If you need help with loading the action for use, let me know! Once you load it, open up your hair files as usual, create your base color (like running Pooklet's dynamite action over a volatile texture). Once you have your new color, immediately use the hair action over it. It should save all your hair files with the new color.
I should note that I use Photoshop CS4, so I'm not sure how this translates into other versions but I would appreciate feedback on that. :)
Download Hair Action
The tutorial pictures are also included in the rar, for ease of access. :)
~Tutorial~
I based my action on a hair that is for all ages, with three texture groups per age, but not hairs are like that. Making a new action is fairly easy, though! :)
I'm assuming that you've created hair retextures before, so you already know what to do in Bodyshop to get a new hair package, retexture/recolor, and import, yes? ;)

1) Create your hair package in Bodyshop as usual. Open up all your hair textures in Photoshop (not the alphas, of course!)

2) Select all the files for all ages. Click "open" and let them load in PS.

3) Run your action of your hair, if necessary, or do whatever you do to recolor. (I typically open up my volatile texture, so all I have to do is run my color over it).

4) Create a new action. :)

5) Choose Select > All (or ctrl+a on pcs) to select the document.

6) Choose Edit > Copy (or ctrl+c on pcs) to copy your colored texture.

6a) A quick side note to point out that the circle must be red to be recording, in case you are new to making actions. If it's not red, then whatever you do will not be recorded and it would be a paint to make an action and then realize that you didn't record it. :P

7) With your hair recolor selected and copied, it's time to save it. File > save or ctrl+s on pcs.

8) In the next volatile texture, simple paste your colored texture in. Edit > paste or ctrl+v on pcs.

9) Merge your layers (Layer > Merge Down or ctrl+e) or flatten them so you can save! :)

10) ...save?
Rinse and repeat the actions of pasting, merging down, and saving for the rest of the action until you've done it on all the hair textures! It may take a while, depending on your computer and photoshop, but you'll only have to make the action once. ;)
Once your action is made, you can create a new hair package, open all of them up as usual, run your color action and immediately run your new hair action! Let Photoshop do its thing and hopefully the actions run faster for you than it does manually pasting in each color like it did for me.
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I hope you guys can find some use out of this! I don't know how this works for macs or older photoshop users or those that use different programs, but I'd appreciate feedback on it.
I hope I didn't make the tutorial too confusing! If you need help, drop me a line anytime and we'll work together. :) Thanks guys! o/