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Thread: Blue patch and spots on glass negative plus some other questions

  1. #1

    Join Date
    Nov 2018
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    3

    Blue patch and spots on glass negative plus some other questions

    Hi, everyone. I’ve got some problems with a glass plate negative.

    Firstly, the image is very sharp but it has a blue patch in the middle and blue spots scattered elsewhere. The patch shows up as orangey-yellow on the physical negative, and I know it’s not a scanner problem because the previous owner had a copy printed in a lab about 10 years ago and it has the same blue patch in the middle of an otherwise black and white print. How do I get rid of it in photoshop? I’ve tried adding a black and white adjustment layer but, while the blue patch is somewhat disguised it is still fairly obvious due to tonal and shading inconsistencies with the surrounding image. Attempting to treat it as a colour cast affected the rest of the photo as well, making the discrepancy worse.

    Secondly, is there any way I can rescue detail from the overexposed edges? It looks like some is there but the overall brightness makes it harder to make out. Is there some way to lower the exposure for those edges without affecting the rest of the photo? I'd like to have this printed out quite big (the negative is about 4.5 x 3.5 and blows up beautifully) so the more image I can preserve, the better.

    Finally, what’s the best way to deal with the weird vertical lines on the left-hand edge?

    Forgive me if these are really basic questions – I’ve looked quite hard on the Internet for answers and haven’t found any!

    Click image for larger version. 

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  2. #2

    Join Date
    Sep 2009
    Location
    Portland, OR USA
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    723

    Re: Blue patch and spots on glass negative plus some other questions

    The vertical lines are artifacts of the plate holder. To get rid of the blue, you can use the channel mixer in monochrome mode and slide the blue slider until it disappears, you can use selective color, choose blue and reduce it, add black to restore density, or you can use hue/saturation, choose blue, and desaturate the color until the cast disappears. All pretty simple to do. Good luck!

  3. #3

    Join Date
    Nov 2018
    Posts
    3

    Re: Blue patch and spots on glass negative plus some other questions

    Thanks, Peter, I'll try some of those things.

    Actually I don't have a plate holder - I simply made a frame of equal dimensions to the Epson frames out of black card, cut a hole the same size as the glass negative, and then put the negative flat on the scanner glass in the middle of the frame!

  4. #4

    Join Date
    Nov 2018
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    3

    Re: Blue patch and spots on glass negative plus some other questions

    Thanks, that fixed the blue thing

    So, how do I fix the overexposed edges of the frame? I can see that part of them has lost all information, but the rest has got detail, such as the floorboards near the base of the photo, that looks like it's disguised by the "glare" of the overexposure. How do I bring that disguised detail back?

  5. #5

    Join Date
    Nov 2015
    Posts
    53

    Re: Blue patch and spots on glass negative plus some other questions

    I don't think the edges are necessarily over exposed. It may be an effect of deterioration caused by storage, or age. I'm just thinking that it would be unusual to have over exposure that affected the edges like this. If it is the result of over exposure, you could try selective application of Farmers Reducer to the negative, but this would be quite difficult, and with a risk of doing more harm than good. I have a collection of plates from the 1920's which have been badly stored. The emulsion surface has deteriorated around the edges of several, giving a metallic sheen. The Orange mark sounds like the same sort of thing, perhaps as a result of inefficient fixing at the time of processing.
    Alex.


    Sent from my iPad using Tapatalk Pro

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