Critiques - - An experiment to enhance subject lighting

duwayne · #1 06-15-2007, 01:17 PM

I’m looking for comments/critique on both the results as well as the process.

I have been trying to enhance the natural lighting in a photo to make the subject stand out more (not to create new lighting). I thought I could do this with Curves but was getting some adverse color changes so I took another approach. I created a layer mask using the Threshold Adjustment Layer for the upper 1/3 of the pixel and another for the lower 1/3. I then applied a Gaussian blur to both masks and then did a Levels Adjustment to the image portion of shadows and highlight.

I have attached an example (before/after) of a photo previously posted here on RP. The following is a step-by-step description.

1) Duplicate background and label HIGHLIGHTS

2) Duplicate background and label SHADOWS

3) Add Adjustment Layer => Threshold on top of stack

4) Select Threshold adjustment layer. Double-click to open dialog box and move the slider to the right (to about 160)

5) Select => All followed by Edit=>Copy Merged

6) Alt click on the Highlights Mask Layer then Edit=> Paste then Gaussian Blur of about 40

7) Select Threshold adjustment layer. Double-click to open dialog box and move the slider to the left (to about 70)

8) Select => All followed by Edit=>Copy Merged

9) Alt click on the Shadows Mask Layer then Edit=> Paste then Image=>Adjustments=>Invert then Gaussian Blur of about 40

10) Select HIGHLIGHTS layer then Image=>Adjustments=>Levels and adjust midtone slider to the left

11) Select SHADOWS layer then Image=>Adjustments=>Levels and adjust midtone slider to the right

There are other things that can be done – Changing blend mode to Soft Light for Shadows and Highlights layer, Adding a drop shadow to the Shadow Layer, blending original image with 30%-60% opacity to reduce the affect or use Curves instead of Levels for more control.

chal · #2 06-18-2007, 05:09 PM

Hi Duwayne.
I was trying to follow your experiment i do've two questions,what do you mean with highlight mask and shadow light?i only see adjument layer,don't see anyother mask.can you please explain to me,thanks.
regards,charles

duwayne · #3 06-18-2007, 07:50 PM

Charles - I have attached the Layers pallet to show the masks. Hope this helps. BTY I am using Photoshop CS. Please ask if you have additional questions.

chal · #4 06-19-2007, 05:00 AM

Hi Duwayne.
Thank you very much.
regards,charles

Swampy · #5 06-19-2007, 07:58 AM

I thought there was too much green in the photo so did a quick levels and used the eyedroppers> Black on the darkest window pane, White on a highlight on her right shoulder and gray on one of the vertical bars in the widow.

duwayne · #6 06-19-2007, 11:02 AM

Very nice Swampy. That's exactly what I was looking for. Did you do this with Curves only or did you use the above procedure? I started out thinking I should be able to use Curves but the colors seem get harsh and oversaturate. I played with the clipping levels (which helps) but these seem to be very abrupt cut-off points. I think the G-Blur on my shadows mask is providing a "gradient clipping". Thanks for the reply.

Swampy · #7 06-19-2007, 12:01 PM

I just used levels, not curves. And I guessed at the true black, white and gray points, but it eliminated the green in her face and hair and brought up the pattern in her outfit and gave her better skin tones.

saby · #8 06-19-2007, 12:44 PM

Matter is the idea what you want to see, IMHO you got it well, i like the after one. To get the result there are lots of ways, now i'll try your way and will ask you about, here is my version, what you can't see on it there were a desaturate a level correction and gaussBlur on the diffuseglow layer and a levels corr on the screen layer mask.

saby

saby · #9 06-19-2007, 02:03 PM

this method works well, but i couldn't get the same color on the face as on the breast what went wrong?

saby

duwayne · #10 06-19-2007, 04:15 PM

Saby - Very very close with your first approach. Colors look very natural. My guess (for your second post) is that the Threshold level for the highlight mask was not high enough causing the face to be masked more than her chest. I have found that some guesswork is involved in selecting the two threshold values.

Swampy - nice work with Levels. I have always used to Threshold function to mark the Black and White points before using Levels. After seeing what you did. I set the Black point using a "not totally black" point in the windows. It works quite well.

Swampy · #11 06-19-2007, 05:10 PM

duwayne... sometimes going by the numbers isn't always the best way. I do it when I'm stumped (especially looking for a 50% gray). Sometimes there IS no absolute black and white, but you can still get crisp blacks by finding something close enough for horse shoes or hand grenades. :-)

Dave.Cox · #12 06-19-2007, 07:12 PM

Sometimes the black white and gray levels can be hard to find. One way to do it is to use the threshold layer, and the color sampler tool. 1. add a threshold layer, and slide the slider to the left, until there are only a few spots of black left, and mark it with the color sampler tool. Delete the threshold layer. 2. add a threshold layer, slide the slider to the right until there are only a few white spots left, and mark it as above. Delete this threshold layer. You now have the white and black levels marked. 3. To get the gray level, add a blank layer, and fill it with 50% gray. Change the layer mode to difference. Now add a threshold layer again, and slide the slider to the left until you only have a few spots of black. Mark it with the color sampler. Delete the threshold layer and the 50% gray layer. You now have the gray level marked. From here you can add a curves layer or a levels layer, and use the black dropper on mark 1, the white marker on mark 2, and the gray dropper on mark 3 to adjust.

If this is confusing, and anyone is interested, I will put a better tutorial together for you later.

duwayne · #13 06-19-2007, 08:29 PM

Thanks Dave - That is the process I used for the black and white points but I have always had trouble finding a neutral point. You've made my day. If you find the neutral point this way and check the info palette, the red/blue/green channels are exactly the same. Just what you're looking for.

saby · #14 06-20-2007, 02:47 AM

Hi Duw,

i tried what you told actually somehow i couldn't get that quality of result what U got. Than i tried this, based on your method

saby

duwayne · #15 06-20-2007, 04:35 AM

Saby - I like your approach of using curves instead of Threshold to generate the masks. It removes some of the guesswork. The masks are also not pure black and white so it takes less Blur to blend. Using your Curves approach and less blur I got the attached results. I also added a Color Balance Adjustment Layer on top to boost the Cyan and Blue (the slight green color cast has bothered me ever since Swampy mentioned it).