The Green Challenge

wmstumme

Okay fellow Dgrinners:

You may have read about my issues with the lighting a particular gym in some other threads I've posted in the sports forum. The lights are very yellow and uneven. There are also some windows which let in some natural light, but decreases steadily during the games (which start at either 4:30 or 5:30 pm each week...). Thanks to this gym, I've learned about custom white balance, and have set it each week and it has helped a good bit, and many of the pictures I've gotten are acceptable. (If you want to see the evolution--take a look at the basketball galleries involving the Monsignor Slade girls team on my page: www.willspix.smugmug.com.) However, I will still get some photos which are off on color (and exposure and focus too...).

I've been able to make some head way with post processing--but on several I still get a greenish cast--especially when I have them printed.

So, here's the challenge--can you help me to clean up the following shot--I still think it looks green. I picked this one, because I figure if I can get this one to look decent, I can use the lessons on others. I also picked it because it is a bit worse than many that I want to clean up, and because the subject in the center is wearing black and white which should help as a color cast reference.

I'm including what I was able to do: 1) straight out of camera; 2)My shot at editing (with photoshop elements 2); and 3) after running through neat image (cause it was shot at 800 ISO).

Please let me know what steps you take on cleaning it up so I can try and re-create...

The original is at: http://willspix.smugmug.com/gallery/2415819/2/131971618#131971624-L-LB

Thanks

Will



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3.

corbosman

Here's an example..I got this doing the following:

- First a levels to stretch the histogram
- Hue/Saturation, set Hue to -20 and Saturation to -50
- Auto Colors
- Hue/Saturation, set Saturation to +25

I made no attempt to fix the noise, plenty of tools for that around.

Just a very quick try, problably better ways around With Shadows/Highlight im sure you can get more detail out of the shadows, and maybe fiddle a bit to get the skintones better. This was just to get rid of the green cast.

Cor

Duffy Pratt

The original is much more yellow than green. If you look at the channels, the blue channel is terrible. Here's what I did:

1) Applied the green channel onto the blue channel at 100%, normal mode. This killed most of the yellow cast.

2) Wrote RGB curves to try to get the backboard, a spot on the back wall, and the pants, near neutral. Then I tweaked the same curves to get the skin tones into something approaching a reasonable range. (I used a spot on the neck for the skin tone reading).

3) Switch to lab. There was still a cast on the back wall and in the highlights, so I created a curve. For a mask, I used the L channel (which I overlayed on itself at about 50%). This mask would have the curve work only in the highlight areas. I wrote curves on the A and B channel to get the colors a little better.

(There are still some color balance issues here, but I think what I've got is an improvement. It's hard to decide what would actually be neutral here: the backboard? the wall behind? the stripes on the ref's shirt? All of them could be, but shirts yellow with age and washing, older backboards also tend to yellow depending on what they are made of, and gym colors are all sorts of shades of off-white. It might help if you had a raw file to work with, because part of the problem here is that the jpg has already set the endpoints, which makes a graduated cast which disappears as the image goes to the endpoint.)

Hope this helps,

Duffy

pathfinder

I agree that this image is very yellow - but it is not even, it is less yellow on the right side where there looks to be some blue windowlight. The left half of the image is very yellow.

One trick I use sometimes, is that opposing colors cancel each other out. Magenta kills green. Blue kills yellow.

SO I simply took your file and created a new copy above the background layer with ctrl-J

Then, Image>Adjustments>Photo Filter>Blue I had to use a lot of blue about 50-60% on the filter. If you get the image just a little too blue, you can then use the opacity slider on the Layers Palette to get back to neutral. I watched the Info platte on the refs right shoulder until the white of his shirt approached neutral RGB numbers. I then did a little S-curve to increase the brightness as this shot was significantly underexposed at least 1-2 stops ( hence the noisy original Blue channel)

I posted a thread previously using a Green filter to kill the Magenta in faces in flash photos in which the camera is too sensitive to Infrared. Same principal.

LiquidAir

Zoiks. That shot has some difficult light issues. I did my work on the original. It is here if you want it:
http://gallery.liquidairphoto.com/gallery/2516748/1/132173086#132173086

132173086-L.jpg

1) To LAB.

I tackled the wall first. There were clearly two different colors of light on the wall. So, working left to right:

2) Add a Curves adjustment layer (call this curves 1) move the end points of the A & B channels to take the area around the net neutral.

3) Stack another Cuves adjustment layer (call this curves 2) on that and adjust the ends of the A & B channels to take the area near the window neutral (I assume that is daylight on the right).

The gradient between the light sources is most apparent in the B channel. I took a good look at that and used it to decide how I wanted to balance my two Curves layers.

4) Use the B channel as a guide for a graident fill in the mask channel on the Curves 2 layer.

At this point the major casts in the background have been replaced with a subtle rainbow because my gradient didn't match the actual light pattern. To do a better job I might have started with the B channel and with some cloning and gaussian blur built a better mask, but that is a lot of work. While the background is looking at least vaguely reasonable, the ref has ended up looking rather blue.

5) Add a third curves adjustment (call this Curves 3) layer and tweak the center points of the A and B curves so the stripes on his shirt are white.

6) Tighen up all the Blend If sliders on Curves 3 until the wall turns white again. A mask would be better here, but it would take a while to construct.

7) Add a levels adjustment layer to fix the exposure.

8) Flatten

9) to sRGB

10) to JPEG

Duffy Pratt

Wow. Look at the scoreboard and the chair on the bottom right in these corrections. The clock varies from white to strong yellow. The chair goes through some surprising changes as well, from deep red to an almost pure yellow.

Duffy

LiquidAir

Duffy Pratt wrote:

Wow. Look at the scoreboard and the chair on the bottom right in these corrections. The clock varies from white to strong yellow. The chair goes through some surprising changes as well, from deep red to an almost pure yellow.

Duffy

The clock is easy to explain. It is far and away the brightest thing in the frame. To boost the exposure enough to make the backboard appear white (not gray) you have to completely blow out the clock. Doing that exposure correction in RGB blows out all three channels and turns the clock white. Doing the exposure correction in LAB sends the clock out of gamut, but when you shift back to RGB the hue is mostly preserved in the conversion.

The chair I am not sure about. Color correcting the backboard to white involves some fairly radical shifts in the curves around neutral. The image doesn't provide a lot of guidance for how to extrapolate those shifts into more saturated colors. I know my choices were rather arbitrary; each time I had a choice I leaned in the direction of adding saturation.

Duffy Pratt

I tried this again.

This time, I first applied a false profile, with a 1.4 gamma to lighten it up some.

Then I applied the green into the blue channel at about 55%, in normal.

Then I took the file to CMYK to get the skin where I wanted it with Curves.

Then a trip to LAB, where I killed the cast on the wall with Curves, using Blend if sliders to limit it to the yellow highlights on the underlying layer.

Then I did a curve to increase contrast on the L channel, applied the A and B channels to themselves in overlay mode at 35% to bring back the color some and did a sharpen of about 100, 1, 18.

Duffy

rutt

Duffy Pratt wrote:

I tried this again.

Duffy

That's using all 10 channels & an false profile!

I don't have time, but I might try to use either the A or B channel as a mask for the cast killing move. The sliders are probably almost as good, but a little less direct.

That false profile trick can be very addictive.

Duffy Pratt

rutt wrote:

That's using all 10 channels & an false profile!

I don't have time, but I might try to use either the A or B channel as a mask for the cast killing move. The sliders are probably almost as good, but a little less direct.

That false profile trick can be very addictive.

Yes, it can be. And I did it for a different reason than usual. In response to the obvious idea that the yellow lights had blown out with the curves, I figured I could lighten the image with the false profile and keep the yellow in the light even when doing curves.

Then it turned out that that was not what my problem was. When I first applied the green channel into the blue, I had basicaly already killed the yellow in the light. I forgot to mention a step I took here. To keep the light yellow, before converting to CMYK, I went to LAB a first time and excluded the most saturated yellows (the scoreboard basically) from the Apply Green into Blue layer. I had forgotten about that when I first described what I did.

Duffy

pathfinder

Will,

Are the walls in that gym white or off-white or even a light tan?

I doubt the walls are as white at the refs shirt stripes are myself...

LiquidAir

pathfinder wrote:

Will,

Are the walls in that gym white or off-white or even a light tan?

I doubt the walls are as white at the refs shirt stripes are myself...

I tried that: evening out the cast in the background and white balancing for the ref's shirt. The wall and the backboard both turn a color of yellow that didn't look right to me. With that much yellow in the background the ref's skin appers blue no matter how you balance it.

wmstumme

pathfinder wrote:

Will,

Are the walls in that gym white or off-white or even a light tan?

I doubt the walls are as white at the refs shirt stripes are myself...

Wow--thanks for all the feedback and efforts.

My wife and I are trying to remember--but every time we've been in the gym, it has been under these horrible yellow lights. I know your eyes usually compensate--but in this gym it is still really yellow and noticeable all the time. However, we think the walls were an off-white. They are certainly not white like the ref's shirt stripes. (PS: the shirt looked new/clean--no extra yellow there...)

So far, my wife (and I) think Pathfinder's efforts come about the closest. Although--Duffy, you seem to have the skin tones looking very good.

The lighting is definately uneven. There are only a small number of the lights, and there is not one over the basket in the back--but there is one off to the right. The windows (and the natural light) are actually to the left in this image--but I think it was getting close to 6:15 pm at the time of this shot--and it gets pretty dark by then this time of the year.

In my feeble efforts, I was more interested in getting the ref's shirt B &W, and getting the skin colors correct--although my wife thinks the background in my effort will print greenish-especially to the left. The one thing I kind of like is the contrast that the color in the background (even with a bit/lot of yellow) had with subject. I also don't want to get the backboard and the wall so white that they all blends together.

I've got a lot a re-reading and studying of these posts to do...

Thanks for everything so far.

Regards

Will

pathfinder

Will,

My brother, mereimage, shoots a fair amount of high school basketball, and he will attest that some high school gymnasiums have very, very challenging lighting. Spotty, poorly evened out sodium vapor illumination with patchy spectral coverage, and a bright yellow colored varnished floor beneath the players that reflect that awful yellow light back from below. And frequently rather dark also. I ma trying to remember - did we see colored photos of high school basketball 20 years ago, or was it all in B&W? Most college gymns tend to have much better lighting.

My quick edit of your image was a fast attempt to demonstrate what can be done rather simply in Photoshop Elements. You do not have access to LAB color space in Elements, but I think you can do PhotoFilters, probably.

I know the refs skins tones in my image are not quite warm enough ( but that is easy to fix locally), but I wanted to get the stripes in his shirt white, and let the rest of the image fall where it might. I think the wall and the backstop are darker than the white in his shirt because walls are rarely bright white in gymns, and I think the lighting is darker there than on the refs shoulder. My image still looks just a little too dark to my eye. Monitor brightness will influence us, so I used the pixel data in the Info palette to set the white point in his shirt.