Hello one and all;
I need help from a true expert to understand using the "blending" options on layers. My aim has been to use Photoshop to do true image enhancement/analysis..specifically in this case to try to pull detail out of an image from a film taken at night.
As an example: consider taking a bright light bulb exposed on film, and the image of the light is the typical glowing blob, though you can get an idea of the shape. What I'd like to do is reduce/remove any incidental background hues so all I'm left with is colors that originate from the light source, and then reduce the glare enough to get as much (or any) detail possible from the bulb itself. Sort of like trying to read the print on the bulb, or identify any details, shape, etc..

The most success I've had, which has been pretty good I think, was in taking two layers, using the "replace color" function on the upper layer to replace the dark background to a white (adjusting "fuzzyness" to eyeball the detail level), then, turn the blending mode of the top layer to "exclusion". It does give a purplish hue to the top layer image on a white background...but with the top layer in exclusion mode I get a good image of the underlying light source separate from most of the incidental glow in the raw image.
..But (duh)..I need to be able to explain why it seems to work.

I've played with all the blending modes and do believe there is real potential to get down to the details underneath by using blending of layers, but again, how does exclusion mode or other modes, shield some parts to reveal other details underneath?

Thanks to anyone who can enlighten me.
-Chris

the simplest way I can say it is take
another picture with the bulb "NOT LIT"
then try all your layer options and opacity levels.
If you cant shut the light off-- google one.
NOW- take some time out- chop a pic and enter the contest-- in
a short time around here you'll be an expert.

Scion, you do realize the name of this forum is "Ask the Experts" right?

Oh like so many other people were offering to help.
For future reference people respond much more
generously when the questioner has actually posted in contest.