MERGE

[superdave Profile]

The merge filter allows you to combine two images together using a blending mode and opacity. It is possibly the most important filter because it allows you to combine two pictures.

There are many uses of the merge node, but some common ones include:

• Overlaying textures. You can do this by connecting your main image to the first input and the output of the Scalefilter (created when using "Add Image") to the second input.
• Sharpening the whole image. You can do this by using the 'extrapolate away' blending mode with a blurred version of the image.
• Sharpen specific features of the image. You can do this by using the 'extrapolate away' blending mode in conjunction with other filters and selections.
• Lightening shadows, recovering highlight detail and other spatially varying effects. You can do this by using other blending modes with blurred and processed versions of your image.

[eadams Profile]

What does the Combine merge do? In Photoshop there is no blending mode by that name.

[admin]

Combine is similar to overlay in that dark areas will make a pixel darker and light areas will make a pixel lighter. Some filters always make things darker (like multiply) and some always lighter (like add), but overlay and combine are in that sense neutral. I could bore you with the mathematical details, but anywhere you might use overlay, try using combine instead and you'll end up with a slightly different, but similar and often stronger result.

There are a few other filter types that Photoshop doesn't have. A couple of others of interest (which are hard to replicate in photoshop) are extrapolate and extrapolate away, which take the difference between two pictures and make it greater. So for instance extrapolating away from a blurred version of a photo, makes it harder, which can be used for sharpening or increasing the clarity (in Lightroom nomenclature).

[eadams Profile]

Perfect! Just the kind of help I was looking for! And Extrapolate was the next merge mode I was going to ask about

Thank you!