I develop realtime virtual fish. I use GIMP to add transparency, etc. Here is a problem I never can do well. Look at the low res image of the tail. The end of the tail is semi-transparent. You will notice the tip it is green but really that is the background showing through. I want to remove the green without hurting the ribs of the tail which are slightly darker.
If I use eraser with less opacity it works but the ribs are lightened and it is just lighter green. I also tried fizzy select but that takes all of it away. I want to remove the green so fish tail is semi-transparent. Is there a way with GIMP to do this?
One way to do this is, if you select the green areas you want to change, one way is to go to Colors>Curves>change the channel from Value to the RBG colors, select Green and drag the bar to the right and down. This will remove green pixels from the selected area. You might want to play with Hue/Saturation after that.
I looked at the image close-up and the resolution is very low. It would be a lot easier to select what you need with a sharper image. You might want to look at selecting with a mask on YouTube, but...
You might also try changing colors via the RGB channels--YouTube has this as well. Is there any way you can get a photo with higher resolution? The current one is so low that the color pixels are all mushed together and hard to separate out.
Try:
Select the green you want to remove (Color Picker Tool)
Change brush mode to Color Erase.
Adjust the brush's opacity.
Pass the brush over the desired area.
I use what images I can get for free and it looks good in my aquarium. Krikor, your suggestion works great, It's too bad you can't color pick then change it to another color needed. Like change green to exchange for color I want at the same time, but this works well.
Thank you.
Th is is just a speculation, but I wonder if you could take the original photo (as a png) and copy and paste it into a new document of thesolid correct color you want. Then this color would show through the tail in the more transparent parts. Then select the area around the fish and make it transparent and save the whole as an png. best to size up the photo to at least 3X so you can better see what's going on.
