Printing exposure time

[zauhar]

I am perplexed by the variation in print time between matte and glossy finish paper. (I asked about this in another thread, did not see a response.)

Recently, I was futzing with one image on Arista RC variable contrast Matte finish paper, and needed ~40 sec exposure time (enlarger lens at f/16, two minutes developing in 1:2 Dektol, #4 filter).

Next I switched to another image, but using Ilford RC glossy paper. Exposure time is very short (10-15 sec) and results are very sensitive to the time. Other parameters the same except the choice of filter.

Does this sound right to you more experienced folks?

Thanks!

Randy

 

[jb17kx]

The papers are different (unless the Arista paper is also Ilford Multigrade IV RC).

I've had exposures vary from between packs of the same paper, and indeed had it drummed into me never to test from a pack if you're not printing from the same pack.

 

[gns]

My experience is that paper speeds are quite variable. Even for the same manufacturer.
Just switching to a new lot of the same product, I would not assume the speeds to be the same.

Yes, with a shorter time, you will need to be more accurate.

Cheers,
Gary

 

[Ljós]

Yep, different papers... also, taking the filter into account, the difference is less than two stops. 40 seconds sounds awfully long, but if you think in terms of stops it is not that big a difference.

Out of curiosity: what enlarger lens are you using? How did you decide to use f16?

I agree that I would be not so happy about a 40 second exposure time, I like mine to be in the 10 second range.... but I am not dodging or burning, if one does that, than longer times are of course the way to go for better control.

Greetings!
Ljós

 

[Pablito]

if you used both surfaces from the same brand you would find the exposure time very similar. Also, f16 is not an optimal aperture for printing.

 

[nikon_sam]

What every one else just said...

 

[zauhar]

Guys, thanks for the advice. Regarding f/16, why is that not optimal? I thought that would give me the largest DOF, so the precise focus position would be less critical. Also, with the one paper I am already down to 10-15sec exposure, so wider aperture would get me down to only a couple seconds.

I will accept that I need to test for each new pack of paper, I guess I would do that anyway.

Randy

EDIT: I just did some quick googling, and I see that the consensus is that enlarger lenses are not at their best at the extremes of aperture setting. I will give it another go. I have a cheap enlarger, but it has a decent Nikon lens.

 

[Ljós]

Randy, just saw your EDIT where you let us know you are digging into the depth-of-field/sharpness-tradeoff regarding to enlarger lenses... The proof is of course always in the print, and it is entirely possible that at f16, with your negatives and your printsize, quality of prints is fine.
One thought: if it so turns out that you want to switch to, say, f8, consider the possibilities of using a lightsource with less wattage. This would also produce less heat, reduce possible warping of the negative.

All the best, Ljós