| Photography Forum: Darkroom Techniques Forum: |
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Q. Enlarger troubleshooting
Asked by Katrina Gulliver
(K=30) on 6/12/2004
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Hi everyone,
I don't own a darkroom, but I hire one. My issue is scratches on my pictures, I know some of these can be the result of scratches on the negatives. However, I was wondering whether scratches on the enlarger lens could be the culprit - how could I tell? Also, if using filters, will a scratched or dirty filter (gel) show up on the print?
thanks.
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ann clancy
(K=2014) - Comment Date 6/12/2004
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You can take the lens out of the enlarger and hold it up a strong light at an angle and you will see if it has any flaws; and if it needs cleaning.
And yes, if the filters have serious scratches they will appear on the print. Check with the person who is control of the lab and find out how often they check the conditions of the filters and how often they remove damaged filters.
We check filters every quarter and have to replace almost every grade filter at each work station.
Just take the filter and hold it up a light source and you will be able to see the condition.
Some of my advanced students bring their own filters as it is very common for beginners to scratch them. After all these are gels and are delicate.
You could wipe the gel filter with a photo cloth, but you can't use any type of wet cleaning process as they are dye and it will run.
If you are using RC paper be careful with washing them. If you get too many in a tray they can scratch each other; and some papers are more prone to scratching than others.
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Katrina Gulliver
(K=30) - Comment Date 6/12/2004
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thank you for those suggestions. The filters are in boxes for general use, and as the place is used for photography classes obviously they tend to be dirty/scratched. I will examine the lens as you say.
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Phillip Cohen
(K=10561) - Comment Date 6/12/2004
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Katrina, scratches on the final image are rarely caused by scratches on the lens as any dirt or scratches would be extremely out of focus. Dirt and scratches on the lens will appear as flares or a general loss of contrast in a wider area of the image. If the rear of the lens is scratched you can take some black India ink and fill the scratches then wipe off the excess. This will keep the scratch from causing a lens flare but will not hurt the image itself.
Most likely your scratches are coming from dirt or scratches on the bottom edge of the condenser closest to the film or if using a difussion enlarger, the translucent white plastic sheet closest to the negative. Either of these would be close to the focus point of the negative and cause you to see fairly sharp scratches in the image. Filters may cause the problem however it is less likely for above the lens filters to cause them as they are also out of the focal plane of the negative. The closer they are to the negative the sharper the scratches would be. Dust and dirt on under the lens filters will show more detail, kind of like making a shadow puppet on the wall with your hand.
As mentioned above, when processing your prints, make sure you don't scratch them on other prints.
Here is a test to see where your scratches are coming from. Insert a negative in the enlarger and focus it on your easel to make a normal 8x10 print or whatever size your normally make. Remove the negative and stop the lens down to F16 or smaller. Expose a sheet of paper so that it will produce a light to medium gray tone. After your develop it and fix it for a few moments and making sure no one else messes with it, take it out into the light and check for scratches. If you see any then the enlarger is causing them and should be cleaned. If there are no scratches, finish the fixing process and cleaning process as normal. If you then see the scratches show up, it is time to let the other students know what they are doing and messing up your prints. Check out the wash process completely and make sure the washing machine if you use one is not causing it. Also if you tend to squeegee off your prints, make sure that you are not causing it. The emulsion of a wet print is just as delicate as that of wet film. So treat it very carefully.
Good luck and let us know what you found.
Phil
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