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Photoshop Tip - Correcting Exposure


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#1 james

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Posted 21 January 2003 - 11:15 AM

I'd like to start a "series" here in the techniques and tips section for "Photoshop beginners." Please feel free to start new threads with tips of your own. Please start your Subject line with "Photoshop Tip - "

Underwater it is not always possible to get a perfect exposure and sometimes, a truly interesting or valueable shot may be under or overexposed. First tip - if you exposure is off, then err on the side of underexposure. You can always "bring up" this kind of shot, but an overexposed shots actually "loses" information. White pixels hold no info...

So, assuming you underexposed a shot, the best way to recover it is NOT to use the Image->Adjust->Brightness/Contrast, it is actually to use:

Image->Adjust->Curves

or

Image->Adjust->Levels

When using the latter, you will be looking at the Histogram. For an underexposed shot, you will notice that it is "scrunched" to one side (the black side). You can use the end slider to lighten the shot without losing any information. If the Histogram looks "flat" on one side, then slide the slider over until it just touches where the Histogram starts to come up.

To bring out detail in the shadows, try grabbing the slider in the middle and moving it back and forth. You'll be amazed what happens.

Try experimenting with different settings in Levels and Curves, as this quick posting only BARELY touches the surface.

Keep in mind that if you use "Lighten" or "Darken" it is just adding white pixels, or worse yet, DISCARDING black pixels. In essence, throwing away information from your shot.

Cheers
James
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#2 yahsemtough

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Posted 21 January 2003 - 12:35 PM

You would like to start...I am sure I had suggested this, taking credit eh! Glad to see.
Todd Mintz
tmintz.com
all photographs posted Todd C Mintz

#3 james

james

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Posted 21 January 2003 - 12:38 PM

Sorry Todd, no credit will be given unless a US passport is presented at the time of posting.

Oh!!!!

Blow Leafs Blow!

Cheers
James
Canon 1DsMkIII - Seacam Housing
Dual Ikelite Strobes
Photo site - www.reefpix.org

#4 yahsemtough

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Posted 21 January 2003 - 12:47 PM

Will my wife or son's do? I'm still holding off on getting mine. I just can't bring myself to do it yet.
Todd Mintz
tmintz.com
all photographs posted Todd C Mintz

#5 bobjarman

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Posted 21 January 2003 - 07:04 PM

Bring out details in those shadows!

Ever had an image that was correctly exposed in some areas, and very dark in others? There is a pretty cool method to bring out the details of shadows. Its colled contrast masking and is done as follows:

1: Make a copy of the image to a second layer. (Drag the background layer to the new layer icon.) Name this layer Contrast Mask. It should be on top of any other layers.

2: With the contrast mask layer selected. (The eyball is on this layer) select image/adjust/desaturate. It should turn your image b/w.

3: Now select image/adjust/invert. Your image should now resemble a negative.

4: Double click the contrast mask layer in the layers pallet. In the mode box change the mode to Overlay.

5: now select filter/blur/gaussian blur. Usually around 10-40 is about right, play with it.

You can also adjust the opacity of the layer by double clicking it again to soften or enhave the effect.

Try it! It will soften your images a hair, but it does wonders for those digitals that are simply too dark in some areas.


I picked this tip up from http://www.luminous-landscape.com/ Nice sight for digital!