Photoshop - advice?

[Dr_Sassy]

I need some helps with photoshop technical know-how. I took some product shots and some of photos that I intentionally wanna make them as 'isolated on white'. I set white balance as auto but why do they look like Incandescent mode? (Don't wanna do much of post-process) hrrr I

- used pure white background, ISO 100, RAW format
- light tent with 5000K light bulbs, shadows perfectly killed
- 2/3 of a stop overexposed, no flash.

Some pictures came out fine but I find some photos have blue area(s)...unacceptable levels of chromatic aberration... I tried to use photoshop - curve, level but it doesn't look real...Purple fringing has been eating up my workflow : ( Ever happened before? what have I missed here? Any suggestion?

[yeahrightdennis]

-Ctrl+Shift L for autolevels
-fix the Saturation up or down (in the Image tab), I normally go up.
-do a little Color Balance, if your pictures are too blue then bring the Yellow up
-if you have the CS version then play with the exposure and Highlights
-and lastly a little curve correction is okay too.

- oh if you feel snazzy do a smart blur to soften out the blemishs

[zeusbheld]

Chromatic aberration/purple fringing sounds more like a lens or CCD problem.

agree.

do a little experiment: reshoot, but set a manual white balance on something you know is white (don't know what to use, maybe a card designed for the purpose), instead of using the factory presets.

most "white" things like towels are actually slightly blue, so the color cast might even be in your background fabric (!)

and as ambassador said, fix it in your raw processor rather than photoshop. it's lossless, photoshop throws away data.

[vacanti373]

honest to god...it is dismaying for me. :cry: ..all your comments are truly years ahead of the amateurish photos i play around with!
i honestly need to track this forum, and hope i can one day understand what you are all talking about!
everything i use are a combination of 3-4 "point and clik programs", and i sure would love to be able to reach all your levels of understanding and achievement!.....but when i read tutorials on photshop etc, i just get confused and frustrated!!!!....GRRRRR!!!! :cry:

my hats are off to you all!

[Dr_Sassy]

Chromatic aberration/purple fringing sounds more like a lens or CCD problem.

agree. do a little experiment: reshoot, but set a manual white balance on something you know is white (don't know what to use, maybe a card designed for the purpose), instead of using the factory presets. most "white" things like towels are actually slightly blue, so the color cast might even be in your background fabric (!) and as ambassador said, fix it in your raw processor rather than photoshop. it's lossless, photoshop throws away data.

for example, I have so many elements in one photo.
- my white towel (came out with the blown out highlights... )
- the color of middle part of photo is okay.. looks natural
- the edge of green lettuce has purple fringing effect (white background behind the vegetable)

I fooled camera with one white paper.. didnt work. I got fooled instead hehe I'll have to try to reshoot but to set up like that again it's so difficult *sigh* Thanks for your suggestions : )

[Dr_Sassy]

all your comments are truly years ahead of the amateurish photos i play around with! i sure would love to be able to reach all your levels of understanding and achievement!.....but when i read tutorials on photshop etc, i just get confused and frustrated!!!!....GRRRRR!!!! :cry:

I am not a pro and will "never" claim myself to be one. I got so much to learn about photography and I do know so little. That's why I am here to ask these pro's .. they are centuries ahead me : ) It surely doesnt take days or months for me to study these things. Your photoshop is already good - practises make skills *grin* and I do get the same feeling with Vector stuff, to be honest.

[Neo]

Chromatic aberration/purple fringing sounds more like a lens or CCD problem.

Yes it's usually a lens problem. The different colours of light get bent by different amounts as they pass through the lens, this is usually too subtle to see but at extreme contrast areas like a blown out sky or edge of white object the effect can be very noticeable. It usually looks like purple fringing.

There are programs that have a list of lenses and their chromatic abberation profiles and can adjust the r g and b channels separately to undo the fringing. PTLens is a popular one and it's available as a photoshop plug-in. Although I think Photoshop has this functionality built in now. I use programs called Gimp and BibblePro for photos so I'm not much of a Photoshop expert sorry.

[vacanti373]

interesting you say that neo...i emailed sassy GIMP exe.a few days ago (don't know if she got it)because it looks really good!..maybe better than photoshop or only different in other ways??....but is sure looks good!

[zeusbheld]

spot on, dr. neo.

i've not used PTLens or bibble pro but heard good things about both.

PTLENS is available for download: http://epaperpress.com/ptlens/

you get both the standalone and plug-in version; the standalone can handle RAW files. can use it ten times before they expect you to pay US$15. if i wwasn't clear from their site didnt notice whether there is a mac version.

in photoshop, the "lens correction" filter is under "distortion."

there may be something for free, here, i didnt search this site but it looks promising.

http://www.photo-freeware.net/shiftn.php

[music]

The purple fringing is a lens problem and you'll have to make note of which apertures (f-stops) produce more chromatic aberrations than others - and then avoid them.

For post-processing:

1) In Photoshop CS2, open image in Camera Raw.

2) Press Z to zoom-in on area with fringe.

3) Click Detail tab on right side; set Sharpness amount to 0%.

4) Click Lens tab; Option-click on Blue/Yellow Fringe slider and drag it left. This will neutralize purple fringe.

If you have a blue cast in your images (not blue fringing), your white balance setting was incorrect. Use Camera Raw to fix the problem with the Temperature and Tint sliders.

Beyond that, I'm lazy so I use a plug-in called iCorrect EditLab Pro for 95% of my non-RAW color correction tasks. It also comes in a stand-alone application for batch processing a lot of images. You can download and try demo versions:

http://www.pictocolor.com/products.htm
http://www.pictocolor.com/learning.htm

If that's too much trouble, send me an image with the worst blue cast and I'll color correct it. Then you can see the plug-in's effectiveness.