Blending Channels for layered images

jdryan3

I am trying to use Scott Kelby's Blending Channels (page 158 The Photshop Channels Book)for bracketed exposures. I follow the tutorial, split the slider and I get bleh! :puke

Well, what I get is a posterized image. If I drag the red channel slider down from even 255 to 230, it gets ugly fast. No matter how far I bring it up or down, no matter the range between the split slider, it looks bad.

I am opening up 16 bit images directly from ACR, Blend mode is normal (I tried others), etc. Ironically I looked up the technique in the book because it seemed to me that "Blend If" would be a great way to handle over/under exposed bracketed images.

Obviously I am doing something wrong. :scratch Thanks for your help.

David_S85

Just out of curiosity, have you tried using Scott's own two photos he used in the example on pages 158-163? If so, what were the results?

Richard

I haven't read the Kelby book, so I don't know how this example is supposed to work, but I have some experience combining bracketed images. I get better results using channels as masks than using layers in normal mode and using the blend if sliders to control the mix. "Blend if" mixtures almost always give me abrupt changes in lightness somewhere even with split sliders, whereas masking one of the layers generally avoids these transitions. Usually I put the brighter exposure on top, then using apply image, I add a mask to that layer from an inverted copy of whichever channel gives me the best blend. It is important to realize that this is only the first step, as at this point the result will tend to be flat and dull looking. You can load the mask as a selection (or its inverse) then create a curves adjustment layer to bring some life back into the image.

Hope this helps.

jdryan3

David_S85 wrote:

Just out of curiosity, have you tried using Scott's own two photos he used in the example on pages 158-163? If so, what were the results?

David - No I haven't. One thing about his image vs mine is the under/over exposure on his is top and bottom. Mine is throughout the image.

rsinmadrid wrote:

"Blend if" mixtures almost always give me abrupt changes in lightness somewhere even with split sliders, whereas masking one of the layers generally avoids these transitions. Usually I put the brighter exposure on top, then using apply image, I add a mask to that layer from an inverted copy of whichever channel gives me the best blend.

Richard - Abrupt is a very good definition. I hadn't done that before on the channels. I had done it on the layer mask of the lighter image on top. I've discovered playing with the mask opacity ( and brush flow/opacity) really helps a lot.