Attached Link: screencap of my settings example

For those who don't but need the solution, here goes.

Having been unable to find a free on-line tutorial on how to avoid using an external graphics editor ( Photoshop, GIMP, paintdotNet, etc etc etc,  ) to create transparency maps, I set about fiddling with settings to solve my problem.

The solution for Poser 6 and up, using G2 Koji as example, and a tattoo (extracted from Tribal Brush Set by alwinred using ABRviewer), may be found in my example screencap.

You do NOT need to create a transparency map in an external graphics application.

Nice Infinity.
The Math Subtract function inverts the image?

erm.
your using the tattoo AS a transmap. you still need an external editor to make the tattoo in the first place.. that includes 'extracting' it... sorry...

Quote - erm.
your using the tattoo AS a transmap. you still need an external editor to make the tattoo in the first place.. that includes 'extracting' it... sorry...

I didn't create the tatto, just took it from an archive created by someone else.  I did not have to go and create a Negative, then save as transmap.  

I only needed to use just one image.

Quote - Nice Infinity.
The Math Subtract function inverts the image?

Correct.  

No need for extra step to create the transmap using an external graphics editor.

Just make the U and V adjustments ( yellow comments on my screencap in first post ) to change the size and position in relation to the body texture. 

Good job, that looks amazing!

Neat trick. Thanks infinity.

I would not refer to what you are doing as making transparency maps because you are not using the transparency node to make any part of the model transparent.  You are blending images.

Also the math node isn't needed.  You can just flip what you have plugged into the inputs on the blender node and then just use Image_Map_2 plugged into the Blending.

If your tattoo is lighter than black or a multi-coloured image, it may not have high enough contrast to produce a strong blend, and the underlying colour will tend to wash out the tattoo colours somewhat. The top Blender node in the image shows this. (I've just used a simple colour for the underlying skin colour).

But if you plug in a Bias node with a very low Bias value, it will create a high-contrast version of the original image, in which everything but the white background is converted to nearly black. The Blender_2 node shows the high-contrast version, and you can see the tattoo colours are blended at near enough full strength.

You can invert the Bias node to produce a "transmap" if you needed it.

Instead of Bias you could use Floor so the everything that not white is made black.

Also you can add tattoos by multiply textures as shown in this thread http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2313758 which is listed in Sticky: Material Room, Nodes & Shaders - Tutorials and Discussions (Bookmarks - Updated)

Multiply is an alternative way to apply the tattoo. Compared to using the Blend node it will darken all the tattoo colours by the value of the underlying skin colour, and that's fine if it's the effect you want.

Just for reference - an earlier tatoo blending shader discussion.

http://www.renderosity.com/mod/forumpro/showthread.php?thread_id=2716576