Contrast Ratios for Printing B&W

SilverEF88

TPF Noob!
Joined
Apr 4, 2011
Messages
189
Reaction score
16
Location
Eastern Oregon
Can others edit my Photos
Photos OK to edit
Alright so I am making some prints from a few rolls of 120 Efke 25 that I shot with my Hasselblad. The prints I am going for are about 14"x14" and I have been doing a contrast ratio of 3 1/2. What I need is the contrast at 3 1/4, does anyone know of the formula to find the contrast ratios? If so I would be extremely grateful. Thanks in advance.
 

ann

No longer a newbie, moving up!
Joined
May 14, 2007
Messages
4,263
Reaction score
189
Can others edit my Photos
Photos NOT OK to edit
If you mean paper contrast you have two options. One will depend on the type of light source your using. If it is a color head or a VC head, you can just dial in any grade you wish. If your using graded filters then you are pretty much stuck with the filter grade.

In the old days of graded papers we would sometimes underexpose and over develop to add 1/2 step of contrast. You could try this with VC papers, some might be responsive, others not so much.

We have tried this in our lab and it has worked and it has failed. Too many variables to be considered.
 
OP
SilverEF88

SilverEF88

TPF Noob!
Joined
Apr 4, 2011
Messages
189
Reaction score
16
Location
Eastern Oregon
Can others edit my Photos
Photos OK to edit
Ok it is a color head and off the top of my head cyan stays at zero, yellow is at 15, and magenta is at 75; for printing at 3 1/2 contrast. I am using VC paper and am printing at F8 for 25 seconds at that contrast. My highlights are slightly blown out and I am thinking that going 27 seconds at like 3 1/4 contrast would be perfect, the problem is I just have a chart with half steps going up on the contrast from zero to 4 1/2. So is there a formula to find 1/4 steps on the contrast? I imagine that it would be something like 25 yellow 65 magenta but want to know for sure. Thanks
 

ann

No longer a newbie, moving up!
Joined
May 14, 2007
Messages
4,263
Reaction score
189
Can others edit my Photos
Photos NOT OK to edit
the paper your using should give you some recommendations for what amount needed. for example, with ilford rc, we use about 33 magenta for grade 3 paper, no yellow, just magenta.
With the color head you can dial in any amount of magenta, you will need to test to see what works best on your enlarger head.
65 magenta is more than a grade 3.5 filter.

I would just tweak the magenta a bit, the times should stay the same. If the highlights are over exposed then you just burn them in after the initial exposure. How much will depend on how dark you wish them to be. Burning in highlights take a lot more light than dodging for shadows.

For example, using your 25 secs for the basic exposure, and you want the highlights brought down 1 stop you would burn in 25 seconds to just that area. One stop is 50 seconds, but then you subtract the initial exposure.
 
OP
SilverEF88

SilverEF88

TPF Noob!
Joined
Apr 4, 2011
Messages
189
Reaction score
16
Location
Eastern Oregon
Can others edit my Photos
Photos OK to edit
Alright I will try just tweaking the magenta a bit. Alright well I will keep playing with it. Whats the saying, "if it was easy everyone would do it".
 

ann

No longer a newbie, moving up!
Joined
May 14, 2007
Messages
4,263
Reaction score
189
Can others edit my Photos
Photos NOT OK to edit
Right, and learning to print takes time and practice, and it doesn't help if one is working on their own.

A lot of my students have their own darkrooms or, soon build one shortly after taking a class, but find it has helped to be with others face to face to assist in the learning process.

They still have to fill the "learning bin"
 
OP
SilverEF88

SilverEF88

TPF Noob!
Joined
Apr 4, 2011
Messages
189
Reaction score
16
Location
Eastern Oregon
Can others edit my Photos
Photos OK to edit
I have the privilege of working with a very knowledgeable film photographer and he guides me as much as possible. The great, albeit sometimes frustrating, thing about working with film is the many different variables involved in making a notable print. It is why I love it. Thanks again for your help.
 

compur

Been spending a lot of time on here!
Joined
Mar 6, 2008
Messages
3,945
Reaction score
883
Location
L.A.
What I do:
When printing I control highlights by adjusting exposure and control shadows by adjusting contrast.
First I get the highlights right via exposure. Then adjust contrast to get the shadows right.
 

ann

No longer a newbie, moving up!
Joined
May 14, 2007
Messages
4,263
Reaction score
189
Can others edit my Photos
Photos NOT OK to edit
good to know you have someone handy.
 
OP
SilverEF88

SilverEF88

TPF Noob!
Joined
Apr 4, 2011
Messages
189
Reaction score
16
Location
Eastern Oregon
Can others edit my Photos
Photos OK to edit
I wish I wasn't sick, I am dying to get in the darkroom and make some prints. I am going to try a couple of different ways to get my highlights under control, including what ann and compur have suggested. Guess we will see what happens.
 

STM

TPF Noob!
Joined
Dec 4, 2009
Messages
317
Reaction score
72
Location
Pensacola, FL
Website
www.scottmurphyphotography.org
Can others edit my Photos
Photos OK to edit
Although every colorhead is different, here is a list of filter combinations I use with my Chromega B Dichroic. You could always use these as a starting point. And of course if you want say, 3¼ instead of 3½, you could always try around 50M. In all honesty, however, I don't think you would see any difference between 3½ and 3¼. HTH!

filtration.jpg
 
Last edited:

Most reactions

ClickASnap

New Topics

Top