Problem with enlarging T400CN negatives

[maxby]

I have this strange problem with enlarging a T400CN negative. I was doing a 9.5x12 enlargements with this negative. Random black spots appeared all over the picture. I have printed 6 prints and notice that the black spots are not in the same fixed pattern.

At first I thought the chemicals were the problem. I have used fresh chemicals from a fresh supply but the problem still persist. Next I changed different batches of papers, I have even used a 11x14 paper but to no avail.

I made another enlargement from a T-max negative and the problem disappears. So I can conclude that the problem does not lie in the chemicals or photo papers.

Calling all the sifus out there. How can I solve this problem or is the problem inherent to this type of negatives?

 

[Bob Carnie]

this sounds like a very strange problem.
Black spots are plus density on the print which could be pinholes in the negative. but you say the holes move ? The only thing I can think of right off the top is stray light in the room ? or look up at the enlarger from the base board (back of your head on the easal) turn on the enlarger, do you see any raw light?
are the spots pin point sharp, fuzzy diffused, large or small?

 

[maxby]

The spots were small and difused like 1mm in diameter. There is no distinct pattern. This has not happened with other true B&W negatives that was printed right after this particular negative. The exposure time was about 40 secs. for both the 2 negatives. The only other variable was that the TCN negative was printed with a 4.5 grade dialed in while the other negative was printed on grade 3. Hope this helps...

 

[Bob F.]

If you have a glass carrier it could it be Newton's Rings - if so, try it in a glassless carrier or without the glass on the non-emulsion side if you don't have a glassless one.

Bob.

 

[Donald Qualls]

I'd expect Newton rings to be light on the print, and to show the distinctive multiple ring configuration (not to mention being a good bit larger than 1 mm on the print). If they're not always in the same place, they pretty well have to be a problem with the paper or the process -- developer droplets splashed on the paper before exposure, static sparks exposing the paper, something along those lines. Changing negatives may be inconclusive because you might have tightened up other parts of the process at the same time (possibly without realizing it).

 

[maxby]

I took out the upper glass of the negative carrier as suggested. The situation has improved but I can still find some (reduced) small blemishes on the print. Having compared this with the earlier prints (total 7 nos), the blemishes are all at different locations on each print. Could be the fault of the negative..?

 

[Claire Senft]

Are your negatives, glass and working conditions free from excess moisture or humidity? Just a thought.

 

[TheFlyingCamera]

I've shot hundreds, if not thousands, of images using T400CN, and I've never had a problem like you describe. I once had a problem with the early Ilford version, XP2, where it had pinholes in the emulsion, which created very distinct, sharp dots. I'd try going completely glassless with your negative carrier, and I'd also suggest (assuming you are using a condensor enlarger) disassembling and cleaning the condensor assembly and mixing chamber, just in case you're getting some dust floating around. What would be most helpful in trying to diagnose this is if you could post some examples of the problem - can you scan in a print or two?

 

[grahamp]

Black marks on the paper implies clear spots on the negative. If you cannot see them with a magnifier, it has to be the enlarging or processing step. If two identical prints show spots in different locations, it has to be a mobile effect - light or chemistry.

Does your enlarging exposure time climb a lot when using T400CN compared to T-Max? If so, I think you have a sunny day and pinhole leaks in your darkroom. The longer handling / exposure time would show up things you might not otherwise notice.