0

this is my first post here!

I am working on a fish project - sand goby, that is semi transparent, see the extent of the fish transparency on different kind of background: additional images to show the transparency of the fish enter image description here enter image description here

I have several images like this: sand goby on white background

I would like to use the surrounding white background (to the left of the fish for example) to somehow proportionaly change the level of transparency of pixels within goby fish - where the fish is brighter there should be higher level of transparency, as a value of alpha channel for that pixel. So if I use the fish png as overlay on other color background the fish would get colored proportionaly in transparent areas

I was researching a bit, and found this How do I create a transparent image that is the diff of two images in gimp?

but that results in selecting the portions that are different from background, whereas I want the level of transparency -alpha channel in the whole region based on similarity with given background, so I could place the png on different background and get similar outcome as in above images of gobies having different coloration on different backgrounds.

Kind of like having a glass object, and trying to place it on different substrates...

Is this even possible in GIMP, what kind of tools would you suggest? I know some coding in openCV, PIL, but not to such extent.

Final goal would be to use the png as a texture for blender 3d model of sand goby.

Any help is highly welcome!

0

Possible technique:

  • Load the fish layer
  • Add a layer above it, fill it with the color of the background, either:

    • Sample the background with the color picker on a wide radius, and bucket fill your layer
    • Copy/paste a portion of the background and blur it heavily (you can use Filter>Blur>Pixelize and use the layer size to average it)
  • Set the top layer to Color erase mode
  • You can put the two layers in their own layer group
  • You can insert a background of your choice at the bottom

enter image description here

| improve this answer | |
  • thank you very much! it works quite well! – Eager Apr 9 at 19:26
  • 1
    @Eager Please consider "accepting" the answer, then. This marks the question as having a satisfactory answer. – xenoid Apr 9 at 19:46
  • done! did not know how it works exactly – Eager Apr 20 at 13:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.