Product shot processing question

[lkeeney]

I did my first jewelry photo shoot the other day for images for a website I designed. Unfortunately in my post processing, I tweaked the exposure of each image a little while looking at the necklace in the images. This was fine until I put the image on a web page where I found the exposure of the necklace stand is a little different in each image.

Does anyone know of a way, in Photoshop, to match exposure of a particular area of different images?

Here is a link to the images as they appear on the web page:
Tracie Murray

[mistermonday]

Since the images are shot on the same background, the colors are the same and only the luminosity is different. Actually the color is different because the luminosity has changed. But if you adjust the Luminosity, the color should pull right back in line as well. One of the easiest ways to do this is to temporarily take the image into LAB Coloradd a Curve adjustment layer and just adjust the L channel.
See the example below. I set a eyedropper sample on roughly the same area on two of the images. The A and B channels were with in a couple of points of each other but the lightness on one was 71 while the other was 81. I just set a point on the curve and nudged it up with the up arrow key until it reached 81 or I could have just dialed 81 into the value box. Guess what, the A and B channels corrected themselves into the exact values. You can use one reference point / set of values to correct all the images so they will match - at least to the point where you will see no difference with your eyes.
Cheers, Murray

[lkeeney]

Thank you very much. I knew there must be a technique to do this, but I never thought of using LAB. I should have thought of this myself because I know LAB has a luminosity channel.

[photolando]

Just curious as to why you used different lighting for some of the shots. They seem to all be made of the same materials and I would think one light set up would work for all of them. Some of the shots have harder shadows than others.

When I shot jewelry, the only things that changed...was the jewelry. My lighting set up stayed the same if it was the same kind of layout.

[lkeeney]

Originally Posted by photolando

Just curious as to why you used different lighting for some of the shots. They seem to all be made of the same materials and I would think one light set up would work for all of them. Some of the shots have harder shadows than others.

When I shot jewelry, the only things that changed...was the jewelry. My lighting set up stayed the same if it was the same kind of layout.

Mike,

I am completely new to jewelry photography. I tried to keep the lighting the same for all the jewlery pieces except for the metal bracelet. I had to remove the jewelry stands for each different piece, and I believe my lighting problem is because I did not mark the exact spot where I had the previous piece setting. They may have been as much as an inch difference in placement. Because I had my softbox so close to the jewelry, that an inch must have made the difference. I could not see this difference in the camera when taking the shots.

My setup was a sheet of black Plexiglas (18" wide x 26" long) setting on a table. I had a large softbox set up on the right side and a sheet of white foam core set up on the left side. I had a sheet of black foam core as my background. This formed a box that was 18" wide by 26" deep with the front and top open. Actually the top was not completely open as I had the white foam core placed at an angle to get some light reflected from the top as well.