One of the characteristics of vertical aerial photography is a tendency for uneven exposure – even the latest million dollar + capture systems exhibit this problem. When you use 1000’s of these images to produce products you can end up with a striped appearance – not good. So along with other (IMO less successful) software tools we use Photoshop to try to address this issue. So far adding a neutral density gradient mask (layer) to the image helps a lot to even overall density. But when this initial unevenness also includes a loss of contrast on the light side you end up with an ‘even’ image that’s contrasty on one end and flat on the other.
So without adding a bunch of screen shots (right now at least) tell me if this can be done:
Image A is good contrast / brightness on left half, light and flat on right. Make image A copy layer. Adjust A copy so that right side ‘matches’ left side of A original. Create a new layer with a ND gradient that approximates what you want to keep/delete (doesn’t matter at this point) and use that as a ‘template’ (not sure if that’s the right word) to modify the image A copy. Like a layer mask?
Oh, one more thing - this needs to 'batchable'
OK - here we go. First a series showing what I am doing, its OK but I wish to address the flatness of the image on the right side
Now a proposed solution to fixing the contrast. Keep in mind a couple things - the original images are huge (300+ mb), that's why using feathered selections won't work (250 px feather isn't enough) and whatever I do must be actionable - i.e. repeatable with variations for images across flight lines. Some adjustments differ more or less as the project dictates.
Hope this helps!
how do I save this adjustment layer/mask combo to apply to multiple images.
Instead of saving the masked AL, you can record an Action of making the AL and its mask, then run that Action as a batch process on a folder of image files. If the images are all the same size and require the same gradient mask and Levels parameter values then only one Action will be needed.
Consider first saving a custom preset of the Levels values that you want. Then when you record the Action, just add the Levels AL and select the preset from the dropdown above the Levels controls then make the gradient in its mask and, finally, stop recording
You run a batch process from File > Automate > Batch...
I think you can run it from Bridge, too, but I've not made much use of Bridge.
Hey thanks for helping me think this through. I use batches and scripting all the time. What is hanging me up is inserting the gradient mask at the adjustment level step - no matter what I use as a source, clipboard, fill from saved pattern or new layer - when I step through the record steps it works, but when I run the batch the level application using the applied mask either hangs or is not applied at all. I'll look into your suggestion in the morning. Please check back, maybe I'll post an .atn
I used the Gradient Tool to make the gradient in the mask which was already targeted after creating the Adjustment Layer. The start and end locations of the gradient were included in the Action without enabling Allow Tool Recording. You might save a custom Gradient preset before recording the Action.
Here's how the action looks in CS6 (I forgot to mention the Save As step earlier). It definitely works in batch mode in CS5.1 on OS X 10.6.8, too.
Update - SUCCESS! At least with recording the complete action and having it play back correctly. I don't know what I was doing wrong before but hey, who cares now, eh?
As someone who has seen the overall quality of this forum decline dramatically over the years I just want to say THANKS for sticking around and helping me out. If there's anything I can do to help in the future I'll be lurking...