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QUESTION:

I use Arista 125 and 400 B&W 120 size exposed at label EI, Rodinal 1: 100 for 15 minutes 20 deg C and 5 sec agitation every ½ min. Then I out it in a SAUNDERS/LPL 67D Dichroic- EFP with ARISTA B&W paper, VC, RC Plus, Glossy and develop in ARISTA developer for paper.

My problem is that I always have to dial in a lot of magenta to make the paper > into a high grade. My negatives have too low contrast. I used to use a condense enlarger, but converted to diffusion since it is supposed to be more forgiving! With condenser I even had more exposure with less development and still had high contrast. I resist exposing to, say ½ of the label EI and increasing Rodinal concentration (time is long enough as it is), since then the contrast might become too high if I should go to condenser one day, with my existing negatives.

My questions are: Is there supposed to be that big a difference between the two enlarger types? Is this enlarger extreme in its contrast requirements or something: Or am I doing something wrong here? Regards B Olsen

MR. GARROD'S ANSWER:

Dear B Olsen,
Thank you for your question that you sent to Freestyle Photo. We are delighted to help you as much as we can. You asked about the contrast difference between condenser heads and dichroic light sources. I have used either dichroic or cold light heads for many years and much prefer using them over condensers. You will, as you have noted, need a bit more contrast in the negatives. I have never found more than approximately one grade difference between condenser heads and the other two, which are both basically diffusion heads. I feel you need to start with a consideration of the films you are using.

Years ago Brett Weston, Bob Byers, and I bought Agfapan 25 from German sources and developed in Rodinal 1:100 dilution. We got superb negatives especially if we used it at EI of about 16 or 1/3 stop slower than the rated speed. This film is very contrasty and benefitted from a compensating developer like this. If you use a film like Arista 125 you will find it is a bit softer and probably could benefit from a stronger dilution like 1:50 or at least a longer developing time than the 15 minutes that you have used. With Arista 400, it is even softer than the 125 film and I would definately go to 1:50 or even 1:25 to get the contrast you need. You will have to try these stronger dilutions and make some tests to see what dilution and developing times work best with your enlarger light head. There is a test for film speed and another for proper film developing times that would pin point these more precisely. If you have access to a transmission densitometer I can give you some instructions on how to proceed. However, you can just do some visual tests and trial and error work to get about the same results, if you have the time.

You should also keep in mind that when using a weak diluted developer like Rodinal at 1:100, you should use plenty of the mixed solution because there isn't as much of the original concentrated developer solution per unit of working solution. When I used that dilution I only put three rolls in a four roll tank or even one roll in a two roll tank, in order to be absolutely certain that I was getting enough developer solution to fully develop the negatives at that dilution. Ansel used to always warn photographers to watch out for that problem when using strongly diluted developers like Rodinal or HC-110. I know a man who uses HC-110 for very contrasty scenes and dilutes at about 1:250 and uses a gallon or more working solution to be sure he is getting enough developer for his 4x5 negatives. I hope at least some of the foregoing makes some sense to you. Keep using the films and chemistry you are using, they are very good believe me - it just takes some fine-tuning and work to get things the way you want them. Thats the fun of photography and we'd like to help you get there...!!!