Larry800

That's a good looking blend, but not what I need. The blend area needs to be around 1/2 inch wide, so it matches the photo as a whole.

Thanks for the suggestion. I would like a more gradual blending. This method smooths out features, and will be worse with a wider blending area.

I demonstrated for myself how easy this task should be for paint.net and/or a plug-in. If you take the three color values (RGB) for a point above the joining line, and the values of a point below it (for example 96,58,41 and 140,88,66) and create 10 equally spaces points between them (the middle is 118 73 54) you get a usable result. I am hoping someone already wrote a plug-in to do this. You select the region and draw the dividing line, and it does a blend - you say how sharp/wide the blend should be (5 points or 20...). I write software, but I haven't written plugins for paint.net. I just don't have time get into this. It would be great if it was a project I was getting paid to do at work - but of course I would still do the research in advance to make sure someone hadn't already done this.

I've spent a lot of time looking for a solution to this. The ones I'm finding would be extremely time consuming (such as using the manual color correction tool, and doing many cuts of the piece being added, using layers and transparent gradients.) Here's an example of what I'm trying to blend. The smudge tool shows how easy this should be - as the colors are already fairly close - but the tool destroys the image when used for this purpose (hair and skin features). Gradient blurring also destroys the features. It is impossible to match up the pieces by adjusting brightness, lightness, and/or hue. The two pieces should be blended towards each other, erasing the joining line.

I have searched for and watched several youtube videos on blending and gradients, and I'm not finding anything relevant. I have attached an image showing the before and after of what I'm trying to accomplish. It doesn't need to be this perfect. The idea is to do a gradient blend (proper terms?) on each half toward the average intensity of the areas closest to the join. Note that it is impossible (in a real example) to match the two halves by using brightness, hue, etc, as there are some slight coloration differences due to different lighting. This example was created by doing a gradient brightness adjustment on an original, even lighted photo (the image on the right), and then taking the original and adjusting the brightness and hue on different sections (on the left - representing the photos to be joined). --- And this is the result I want - gradient brightness (and colors) - as opposed to an even lighting solution. --- Edge matching is the most important thing.