Negative scratches and condensor enlargers

[Greg Nelson]

I tray develop my 5x7 negatives and have my routine down-pat, rarely damaging a negative, and almost never scratching the emulsion side. Occasionally I will get a minor scratch on the base side. Printing on my diffusion-type Elwood enlarger hardly ever resulted in a print that rendered such a scratch visible. I have recently bought a Durst 138G 5x7 enlarger that is just a wonderful, sturdy machine and a joy to use, relegating my Elwood to storage. A recent negative of great promise has a slight scratch on the base side (naturally in a solid sky, near the subject). With the condensor enlarger this thing is crisply in focus and unacceptably visible in the print. I've purchased a Slosher for developing negatives in hopes of avoiding this problem...but is there anyway I can alter my glass negative holder, or place something (like frosted glass) between the neg tray and the condensors above that will deemphasize such small defects? Currently I have clear optical glass below the negative and anti-newton glass compressing the negative flat from above. Any suggestions?

[Bill_1856]

There is a poster on the "APUG" forums, who signs himself in "Noseoil." It is (I assume) an old time monicer from the days when film base scratches were hidden by rubbing a little noseoil into the scratch. Apparently the index of refraction of the two is virtually the same, and scratches disappear like magic. Alternately, if you can find it, Edwal makes a "Scratch Remover" liquid which is applied to the film base and does the same thing.

Wish that I had a nice 5x7 Elwood.

[Joseph O'Neil]

I have had almost exactly the same problem. I have an old elwood 4x5 enlarger, diffusion sytle, and going to an Omega D2, the condensor lens style, same as you - all scratches show up.

In the tray below the main condensor lenses, I have a price of square, frosted glass I placed. It sits above the negative carrier. My carrier is glasses - I personally never had good luck with glass carrier (your milage may vary).

Your scratches still show up, but it is less.

Also, I used to use tray development too, but a condeonsor enlarger sure pushed me to a Jobo tank developing pretty fast. This is for 4x5, not sure what or even if there is a Jobo tank for 5x7.

joe

[Andrew O'Neill]

Well, the solution is simple. Go back to your diffusion system.

[Patrik Roseen]

Some films have 'gelatin'-coating on both sides, e.g. efke pl 100. Is it possible to minimize the effect by putting the negative in water to soak up water and then have it dry again? possible the scrath gets thinner ...or will the negative be ruined?

[Don Wallace]

I recently got exactly the same enlarger and I have been researching the same question. I read somewhere that it was possible to put a sheet of diffusion material below the condensor somewhere but I have not tried it yet. There is also a very elegant solution: Durst makes a cold light attachment that slips into the existing condensor slot. I am thinking of getting one but I don't have a price on it yet. You should contact Jens Jensen at Jensen Optical. Their website is undergoing reconstruction (http://www.jensen-optical.com/) but you can contact him directly at 503 846 1492. He is very helpful and sent me a bunch of manuals and other information in pdfs. He recently sent me a pricelist but it has not yet arrived. If you like, I can forward to you everything I have so far.

[Greg Nelson]

Thanks for the Jensen Info offer. I actually have a bunch of stuff from them and haven't had a chance to weed through it all. I can contact them if I need more. I have read a diffusion source is available but was guessing it cost more than the used enlarger. I probably should look into it though. I might try a sheet of frosted glass below the bottom condensor if I can get one to fit there. It will cut down on the total amount of light reaching the negative, but should approximate the effect of a diffusion chamber, right?
Greg

[Don Wallace]

Greg, I am newbie with this also. The diffusion light source from Durst looks pretty simple so I am guessing you could fake it with a sheet of frosted glass. We should stay in touch as we experiment. Joe said he does it with a D2 so it is worth a try.

On the other hand, the Durst diffusion source looks light it might be worth it, especially since I paid almost nothing for the enlarger.