Re: Reduced Platinum Print Sharpness

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From: Sandy King (sanking@clemson.edu)
Date: 04/20/02-06:27:35 PM Z


Just out of curiosity, did you use the negative in the correct
orientation with both light sources, i.e. emulsion of the negative in
contact with the sensitized surface of the paper. If by any chance
you used the negative reversed with both light sources you would get
much reduced sharpness with the fluorescent bank.

Other than poor contact between the negative and paper and/or use of
a reversed negative there is no reason that you would have greatly
reduced sharpness with a fluorescent bank as compared to the light
from a plateburner. Some people claim that there is so reduction in
sharpness with a diffuse light source but I use both types of light
and if there is any difference at all it is very small indeed.

What Nuarc unit are you considering? I have seen fairly new Nuarc
26-1k units going for $600-800, and these have integral vacuum and
integrator.

Sandy King

>Thanks to all. I will try the suggestions. The sun
>test is a good start. I doubt the print frame to be
>the probelm as I did add foam backing to assure a good
>pressure and flatness. This did not help. Also, these
>are not large prints - 8x10.
>
>I am considering a used Nuarc with Metrolux
>integrator. Does any one have a fair price estimate
>other than "what one is willing to pay?"
>
>Thanks,
>
>Steve
>
>--- Sandy King <sanking@clemson.edu> wrote:
>> As others have suggested the most likely culprit is
>> poor contact
>> between the film and paper. Poor contact can reduce
>> sharpness even
>> with the semi-collimated light sources such as those
>> in plateburners
>> but the problem is much worse with fluorescent banks
>> where some of
>> the exposing light that reaches the film arrives at
>> angles from 45 to
>> 85 degrees.
>>
>> If you are making large prints with a fluorescent
>> bank a vacuum frame
>> will almost certainly improve sharpness. Even the
>> very best contact
>> printing frames can give poor contact with large
>> prints if not
>> adjusted correctly. In my own work I have found that
>> a layer of
>> plastic packing material, of the kind with integral
>> small bubbles,
>> placed between the print and the back of the frame,
>> in combination
>> with a lot of pressure, will provide sufficient
>> contact in most cases.
>>
>> Sandy King
>> --
>
>
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