hi all,

the following might be Piece of Cake for some, but everyone will know someone else who can profit from this. It addresses Poser 9 / Pro 2010 and up.

When you apply an image map to any surface component (diffuse, transparency,  displacement, ...) you will get the option to assign a Gamma value to it. The rule of thumb is to use Gamma cf Render Settings for color use (as for diffuse...) and Gamma = 1.0 for amounts (displacement, transparency, ...).

There are some scripts in Sripts menu that help you to (re)set those values, and various third party tools offer some help as well. That's all fine.

Whatever way Poser becomes aware of the requirement to apply an imagefile, you have to realize that it will import any imagefile only once, and will associate a single gamma value to it.

So, when the same file is referred to by multiple image-map nodes, by various image-map slots for various surfaces or various objects, only ONE gamma can be associated with it. If you make a change somewhere, it's rippled through into all other places that file is referred to.

So, when the same imagefile is used for color purposes as well as for value porposes, say to drive diffuse as well as transparency, then you're in trouble assigning it the appropriate Gamma value for each use. The Gamma is a property of the (Poser ref to the) extrenal file, not of the specific individual call to it.

The only way out is to duplicate the file at the source level, and offer Poser a different file for both purposes. And perhaps... turn the Gamma=1 file into greyscale beforehand.

Excellent post.

Follow up: If you really feel like you have to use the same image both as color and as number, you can let the image associate with and use render gamma (as for color) and then bring it back for other uses with a gamma node.

The image gamma value is used as anti-gamma (as with all incoming material.) Therefore it can be cancelled by connecting it to a gamma node (don't set it to anti or "inverse" gamma - you want to undo the anti-gamma).

The color picture has render gamma on it and goes to Diffuse Color.

It also goes through a (re) Gamma node and then is used as bump map.

Note: I advise against the use of color maps for bump on general principle of being (usually) senseless, but if this is what you need to do, do it like this.

I never knew that.  Thanx for the explanation...

And just the other day I was pleasantly surprised that the change in gamma I made to the transparency of a hair figure had been applied to all mat zones (and it had a lot!) which I was not looking forward to doing one by one.  Now I know why, thanks :)

I don't understand this poster: Does not each materiel zone allow you to alter gamma value? I do not agree that ony one gamma value can be associated with a map.

It is the material zone where values can be set, irrelevant to the tx you import.

You can use a Tx (This or that) image for either diffues or displacement or bump or alt dif or alt spec etc.

If you want flexibility you cannot also have consistenty.

It's true, Poser cannot assign two different Gamma settings to a single image. Has nothing to do with material zones. It was a frequent trick for Hair makers to plug the color texture into the bump channel (if and when they even bothered to think of a bump for the hair model). That doesn't work well now at all unless you use the node setup that BB showed. It's just better to make an actual bump map in your art program. All color maps set to whatever your render gamma is and bump and transparencies (grey scale maps!) set to 1.00 gamma.

Quote - It's true, Poser cannot assign two different Gamma settings to a single image. Has nothing to do with material zones. It was a frequent trick for Hair makers to plug the color texture into the bump channel (if and when they even bothered to think of a bump for the hair model). That doesn't work well now at all unless you use the node setup that BB showed. It's just better to make an actual bump map in your art program. All color maps set to whatever your render gamma is and bump and transparencies (grey scale maps!) set to 1.00 gamma.

It's true, Poser cannot assign two different Gamma settings to a single image. Has nothing to do with material zones. It was a frequent trick for Hair makers to plug the color texture into the bump channel (if and when they even bothered to think of a bump for the hair model). That doesn't work well now at all unless you use the node setup that BB showed. It's just better to make an actual bump map in your art program. All color maps set to whatever your render gamma is and bump and transparencies (grey scale maps!) set to 1.00 gamma.

I really have to argue this: you can assigne differnet gamma values to the same image. What you need to do is save the image under two different names. If you load an in image to the diffuse node and give it gamma value of 5 then attache the displament node to it the gamma value will be as the diffuse. Change one and you change the other This applies even if when you seprate the chanells by uploading in seperate processes. Howwever, save the same image with eg img 1 then img 2 you can act on them sepertaley.

If you use a bump map made in your graphics prog make sure you have the direction of the light correct.

Am I missing something? I don't believe I have a gamma correction option in Poser 9...

@LuckyBears:

"I really have to argue this: you can assigne differnet gamma values to the same image. What you need to do is save the image under two different names."

Thanks for agreeing with me, this is exactly what I wrote in the original post. You cannot associate multiple gamma values from one Poser scene to the same image FILE. Whether multiple files have the same content is something Poser doesn't care.

@Rokket:

Thanks, I lost count. Should be Poser 10 and up. Sorry for the confusion. I'm a Pro user, so I couldn't check directly.