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Author Topic: The Power of the ExpoDics  (Read 10672 times)

Offline Mhayes

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The Power of the ExpoDics
« on: September 23, 2007, 03:55:18 PM »
In an earlier post, I had a picture of my copy stand and lights. That setup included two daylight flourescent daylight tubes with a 6500 Kelvin lamp color. On the Forum I had posted the picture that was taken and was pleased with the results. Unfortunately the way I got those results is not the way that things will be done on the upcoming copy run to Coffeyville, KS. For one, I shot in RAW and then changed my color temperature there to 6500 and it looked great. Things were not so good when I changed my camera setting to jpeg and changed the WB to a temperature of 6500. I could no longer match the results that I had in RAW and I did not like the idea that each picture I used for the practice run had different problems. I also should paid more attention to JohnBoy's comment about color shift.

While researching my problem on the Web, I came across setting your custom WB with the ExpoDisc. There are other ways to do this, put the ExpoDisc got plenty of praise. I happen to have the ExpoDisc and had kind of forgotten about it. I decided to do an experiment doing different WB: ExpoDisc, Auto WB, 5600K, 6000K, and 6500K. The results were stunning! I am posting three pictures that are taken with Auto WB, WB at 6500K, and with the custom WB using the ExpoDisc. Needless to say, the ExpoDisc is going on the trip to Coffeyville.

In case anyone is interested I am included the link to ExpoDisc that has videos on how it works. http://www.expodisc.com/support/videotutorials.php

Auto WB


WB at 6500K


Custom WB ExpoDisc
"carpe diem"

Margie Hayes
OPR President
mhayes@operationphotorescue.org

Offline sanbie

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Re: The Power of the ExpoDics
« Reply #1 on: September 23, 2007, 04:54:47 PM »
Wow  :up: that looks awesome...

SAnbie
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Offline Patre

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Re: The Power of the ExpoDics
« Reply #2 on: September 23, 2007, 05:39:09 PM »
Terrific color adjustment on the expodisc image! :loveit:

Offline Johnboy

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Re: The Power of the ExpoDics
« Reply #3 on: September 23, 2007, 08:11:38 PM »
Marge,

Am I correct to assume that the ExpoDisc copy is the one that is the closet to the original? Auto WB looks to be an acceptable black & white. The ExpoDisc has a sepia tone look to it. Can you post a color copy done with the ExpoDisc? Unfortunately I'm going to be a way for a week so I probably won't get to see it unless I can get to someones computer in a few days.

When I saw your Kelvin listings for the various color temperatures, the 5600 K come to mind that this is the standard Kelvin daylight temperature. I am thinking that the 6000K and 6500K are going to run more blue in color. I could be wrong on all of this as it has been years since I thought of the technical side of light. OPRDave, if you are reading this please correct me if I am wrong.

Another thing Marge, if you get in a situation where you are getting the reflections like Max and the others are experiencing you might try a polarizing filter on your camera lens. You may not get rid of all of the glare but it might help minimize it. Just a thought and it may not have any affect. Polarizing filters work best on single source lights, i.e. the sun, where your copy set up will have 2 lights left & right. Sometimes moving those lights might help minimize the glare. If you do move them be sure the original is evenly lit.

Good luck on your trip.

Johnboy

Offline Mhayes

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Re: The Power of the ExpoDics
« Reply #4 on: September 23, 2007, 08:35:40 PM »
Johnboy,

Yes, the ExpoDisc is the closet to the original--almost an exact copy. I probably should have posted the rest of the pictures. I did do a color temperature of 5600K and it came out with a greenish cast. After I posted the pictures, I happened to think that no one is going to know which picture is correct. The one thing that has troubled me is the fact this picture most likely would have been changed to a black and white, but it is not. It had the sepia tone when it was new. I realize that a lot of the pictures I will be working with will be that color from water or sun damage.

Another interesting note is that on a regular color print, the ExpoDisc still had the edge.

That is an interesting note about the polarizing filter--I have one, but not for the lens I will be using. I also wonder too about the direction of the lights. I was thinking that the light source would be need to be over my shoulder rather than how I am going to have it set up. On this point I am not sure.

Thanks for planting the doubt about the lighting setup on the first post because I kept doing trial runs to make sure that the WB would be correct.

Margie
"carpe diem"

Margie Hayes
OPR President
mhayes@operationphotorescue.org

Offline Mhayes

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Re: The Power of the ExpoDics
« Reply #5 on: September 23, 2007, 09:19:58 PM »
Here are some examples of a color photo using different settings. At first when I viewed the pictures on the computer, I thought that this time the Auto WB had done a fair job. But when I looked at the photo, once again the ExpoDisc had done it right. This is definitely a case of where the lights I have chosen do not work well with trying to match color temps in the camera. I have times when I have tweaked the WB of a picture, but overall have been happy with what I could do with the camera. Even though the lights have proved a challenge; I like having cool lights with 6,000 hour use.

The one thing that really amazed me is that a sepia toned picture was never spot on unless I used the custom WB of the ExpoDisc.



Margie

"carpe diem"

Margie Hayes
OPR President
mhayes@operationphotorescue.org

Offline Johnboy

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Re: The Power of the ExpoDics
« Reply #6 on: September 23, 2007, 10:33:30 PM »
Marge,

Thanks for posting the color copies. Color can be so finicky I just wanted to be sure that it wasn't going to throw another curve at you.

After I posted my last comment I viewed the video. I can see now how it works. When you use the custom white point or white balance you are setting up for an 18% grey which is a standard setting the exposure. So I can see how it helps get the copy right.

In your copy set up it is preferred to have the lights on the left and right at a 45 degree angle to the camera lens axis. This usually will help create even lighting and to minimize the glare but not always. That is when you start to get creative to eliminate it or at least minimize the glare. So as I understand the ExpoDisc once you get your copystand set up you would put your camera on the base (floor I assume) and shoot back to the tripod head with the ExpoDisc over the lens.

A bit of a physics lesson here for trying to get rid of the glare if it occurs. The angle of incidence equals the angle of reflection. In other words the angle at which the light is hitting the subject will give a reflection at the same angle. Therefore moving the angle at which the light is hitting the original may help lessen the glare. So you could move the angle of the light as needed to lessen any glare, but as I said before be sure the original is evenly lit. Even lighting is important. Uneven lighting will throw another variable at the restoration.

Johnboy

Offline Mhayes

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Re: The Power of the ExpoDics
« Reply #7 on: September 23, 2007, 11:04:24 PM »
Johnboy,

Yes, I put the camera on the mat but did not shoot back at the tripod head. The reason I didn't is because my light source is not behind the camera. Instead I sat the camera about where the picture will sit and then tilted the camera to point between the two lights. When you watch the video, you will see him by the model while he points the camera back at the tripod, or where the camera will be held while taking the picture. In those cases, the light is the sun or studio lights.

To save expense I bought the largest diameter ExpoDisc so that it could be hand held on a variety of lenses.

I'm not sure this is as big a factor in digital as it is in film, but by having the ExpoDisc I don't have to worry about the effect of my lights plus those that will be on overhead in the library.

Margie
"carpe diem"

Margie Hayes
OPR President
mhayes@operationphotorescue.org

Offline Hannie

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Re: The Power of the ExpoDics
« Reply #8 on: September 24, 2007, 04:03:02 AM »
Thank you Marge and Johnboy for this very interesting topic, it was fun to read!  After you posted the second set of photos it was really clear how the Expodisc works, amazing!  I also watched the link to the videos, looks like it is worth while to own one of these filters!
About the "white dots", it almost seems like some of the photos of the latest batch were printed on textured paper.  In that case, to reduce reflections it helps to copy the photo a second time at a 180 degrees rotation and merge them together during restoration.

Hannie
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Offline jneil2

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Re: The Power of the ExpoDics
« Reply #9 on: September 24, 2007, 12:01:22 PM »
I enjoyed reading this topic, everyone.  As one of the three photographers on the last copy run to Biloxi, glare was often a huge problem with many of the prints.  Sometimes, the best solution was to move the lights so that the glare was in an area that could be easily retouched, like a plain background. As far as the white dot problem, I never thought about rotating the print and I would like to know more about how to handle that in post.  Some batches were huge numbers of photos, all with the plastic album page stuck to the photos which were all "bumpy"

There is always a lot to learn, and I appreciate reading what everyone has to offer.

Jan

Offline Hannie

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Re: The Power of the ExpoDics
« Reply #10 on: September 24, 2007, 12:58:56 PM »
Hi Jan,

Always thought I could understand everything in English but sometimes s.t. comes up and I'm lost.  Sometime is now!
You said "I would like to know how to handle that in post" and I'm not sure what "post "means in this case.   :-[
 
What I meant by taking the picture twice really is s.t. I learned in relation to scanning photos so I thought it might work with a camera set up as well.  The idea is to minimize texture, it will not completely disappear but it will be a lot easier to work on.
Once you've taken the picture you rotate it upside down and take a second picture.
Then in Photoshop you rotate the upside down picture again to right side up and make it a layer over the first picture.  Of course they need to be lined up and you can do that by using the Difference Blending mode and lower the opacity to about 50%.

Hannie
Hannie Scheltema
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hannie@operationphotorescue.org

Offline schen

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Re: The Power of the ExpoDics
« Reply #11 on: September 24, 2007, 01:18:29 PM »
I am a cheapskate, so I did not buy the ExpoDisc.  I printed a uniform gray on a piece of white paper using a black and white printer.  When I needed to do white balancing, I put this piece of paper over the subject and zoom in onto it.  I drew a cross at the center of this sheet of gray paper using a black marker so autofocus works.  (Once I took the camera off autofocus then forgot to put it back for sometime.)
Windows 10, Photoshop CS6

Offline Mhayes

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Re: The Power of the ExpoDics
« Reply #12 on: September 24, 2007, 01:53:31 PM »
Hi Everyone,

Thanks for all the feedback! I love hearing from all of you and gaining from your experience and thoughts. I found the link that is about eliminating color cast: http://www.macworld.com/2007/03/secrets/aprildigitalphoto/index.php It also list different ways to customize your white balance settings. Besides the coffee filter, it list the white paper like Schen mentioned.

Having glass and the glare could be a real headache. Was the glass nonreflective? Christina mentioned that I need at least a l0 x 13 glass to put on those photos that are curled. Because of that, I am having some nonreflective glass cut to take on the copy run.

Margie
"carpe diem"

Margie Hayes
OPR President
mhayes@operationphotorescue.org

Offline sanbie

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Re: The Power of the ExpoDics
« Reply #13 on: September 24, 2007, 05:45:29 PM »
What a truely fascinating read...

Sanbie
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Offline schen

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Re: The Power of the ExpoDics
« Reply #14 on: September 24, 2007, 09:32:29 PM »
Quote
Having glass and the glare could be a real headache. Was the glass nonreflective? Christina mentioned that I need at least a l0 x 13 glass to put on those photos that are curled. Because of that, I am having some nonreflective glass cut to take on the copy run.

A flat reflective surface is easier to avoid the glare by moving the light source.  I believe that is the reason Christine put a piece of glass over curled photos.  No matter how you adjust the lights, a curled photo will always have some glare.  The non-reflective glass may reduce the sharpness of the photos.
« Last Edit: September 24, 2007, 09:35:24 PM by schen »
Windows 10, Photoshop CS6