exposure button

[Derek Campbell]

Hello,

There is a button on the left side of the pre-scan window labelled "Set automatic exposure (lamp brightness)".

When does one activate this function and when does one leave it alone?

Thank you.

Derek Campbell

[degrub]

Most of the time you can leave it on. i will do the exposure manually only when the image (on a light table) looks like the highlites blew out or if there is more details in the dark areas that i want. Then i may do two passes and combine them in PS, one for the highlites and one for the dark areas. It really depends on what you want out of the image.

Frank

[Derek Campbell]

Most of the time you can leave it on. i will do the exposure manually only when the image (on a light table) looks like the highlites blew out or if there is more details in the dark areas that i want. Then i may do two passes and combine them in PS, one for the highlites and one for the dark areas. It really depends on what you want out of the image.

Frank

Thanks for responding to my post.

Can I assume that if any manual adjustments are made in exposure and or tone, then the automatic exposure can be left alone?

Also, what means do you use in Photoshop to combine two scans, i.e., one for the shadows and one for the highlights?

Thanks again, in advance.

Derek Campbell

[degrub]

AS long as you turn Auto off.

Take a look at Blend modes. Most important is exactly same size image, and pixel registration. Use shift-drag and drop to center the image. if you are lucky they will be perfectly aligned. Use difference to determine when you have the layers exactly registered. Or you can invert the top layer (highlights), set its opacity to 50%. If they are exactly aligned it should be close to all gray. Use the move tool and free transform tool to reposition until you minimize the embossed effect Then you can use multiply or one of the other blend modes to mix the two together to get the picture you want..

The book Photoshop Artistry has a good discussion on blending images. Luminous Lanscape has a tutorial on a similar method at :
http://www.luminous-landscape.com/tutor ... ures.shtml

Happy Blending,
Frank