B&W exposure times

[stark_674]

I use a Durst 601 enlarger with a sivobox instead of sivocon condenser.
It gives a diffused light instead of a condensed light.
To print a 24x30 paper, it is needed 100 sec (using a 100 W lamp)
Do this time songs as normal in this conditions?
Is a diffused light good to print on RC Multigrade papers?
I saw that usually I use 3 to 4 contrasts.
Any suggestion to know if this is a good way to continue printing
Thank you in advance
Stark

 

[Mark Crabtree]

What f stop are you using on the enlarging lens?

 

[Thomas Bertilsson]

As noted by Mark, we need to know what f/stop your enlarging lens was set at.
Also, is it 24x30" or 24x30cm? (I think there are 30" wide rolls out there).

 

[stark_674]

Yes... it is 24x30 cm..... so I think maybe about 10x12"...
My f stop is 4
BTW... I think that I would feel more comfortable with condensed light, I like the sharpness idea but, it is not to simple to find condensers for my enlarger on ebay.
I only have some doubts, sometimes I really expose over 100 secs and on this blog I read usually minor times... bye

 

[Thomas Bertilsson]

Stark, my 35mm enlarger is diffusion as well. And I only have a 75W bulb.

You may want to see what you can do about processing your negatives differently. I have made 9x12" prints a lot lately, and generally my exposure times are somewhere between 20 and 40 seconds at f/4. But if I put a negative in that has higher base fog, like one that came from expired film, my exposure times can be as long as 100 seconds or more, at f/2.8!

So a lot has to do with your negatives. Maybe time to do a film developing test where you develop negatives normally that have been exposed in the camera one stop more, at box speed, and one stop less. See at which exposure you have 'enough' shadow detail - by printing them. Then if your negatives have blocked up highlights, you shoot one more roll at the 'good shadow detail' speed, and develop less.

With a 100 Watt bulb and great negatives, you shouldn't have to expose for that long. Use fresh film for best results.

Condenser enlargers have their drawbacks. Dust, for example. Grain shows up more too. But they are great for other things, as generally they will allow much stronger light bulbs. I have a condenser enlarger for medium format and 4x5 negatives where I use a 250W light bulb. Needless to say, even very dense negatives are possible to print in it.

Good luck!

- Thomas

- Thomas