GIMP Version: 2.10.18
Operating System: Linux
GIMP Experience: Intermediate Level

---

Looking for assistance from more experienced GIMP users: I'm trying to figure out a way to increase the translucence of the material this model in laying in. I've heard of this being done, and I specifically aimed my strobe behind the model hoping that the backscatter would eventually help the process, but I'm not even sure where to start. I have the original RAWs, if that helps. Any assistance will be appreciated. Thanks.

Impossible to create data that isn't there. About the best you can do is duplicate layer, convert layer to B/W and overlay using "Screen" blending mode, then adjust opacity to suit.

Don't know if this is any use: Duplicated the layer, did colour to alpha on the duplicate and picked the mid-red. Put above the original layer and erased the area over the background so that wasn't changed.

Selectively applied Freaky Details and reduced the red in the silk area for this result. Could use a bit more refinement/cleaning, but oh well.

Had to try this - not so simple

I duplicated the layer and colored to alpha the top layer. Then used the LCH Lightness layer mode.

All the other tries are good

Sampled the colour of the model's hand.
Created a new transparent layer above.
Painted over the model with the sampled colour.
Set the upper layer to HSV Hue.

I like your idea so gave Freaky Details a go too:

I like all of these =) They give me something to work with, thanks to all.