Starless Trunk Mosaic

[steppenwolf]

On 12/09/2020 at 10:12, apolkowski said:

Second, the end result is OK, images are nicely combined, but changing parameters in the first expression has no influence on the final image. It means to me, that the change to star mask in expression 1 has no impact on the final result, as PixelMath uses the original starless image for combinantion. So destroying the star mask by the error in expression 1 is not visible in the end result.

Please correct me if I am wrong and my logic makes no sense.

Hi, the two formulae perform the following functions:-

The second line is the blend function which gives an approximation of the 'screen blend' mode found in PhotoShop but running this has a slightly adverse effect on the background brightness so I devised the first line which maintains the original background levels - it is subtle but it worked well for me and most certainly, on the image that I devised it for (which was for a magazine article), it had a positive impact on the image.

Hope that helps.