calibrating a color head for b&w

[coops]

I hope this question makes sense. I have a color head but use Ilford filters for contrast. Ilford provide a list of yellow and magenta color head settings with their paper but I get different results with these settings than I do with the filters that slide into the head. I think it sounds easier to use the filters n the color head, so I want to calibrate it but not quite sure how to do this.
If I expose a 31 step wedge using the ilford grade 2 filter for max black min. time, and then dial in the approximate color head filter for a starting point, I assume I am looking to find the filter comb. and exposure time to make a print to match the one made with the Ilford filter. Am I on the right track? Would I then repeat this for other grades?

[bob carnie]

Yes

or you could take your favorite neg and make prints that match the filter set.
I split print always so giving starting points would not be realistic for your particular darkroom and negative density/contrast.
Pyro negs will give different starting points as well.
have fun
I use the yellow dichroc very infrequently, the magenta seems to be the main filter.
Cyan filter is never used in my Darkroom other than dialing in ND.

bob

I hope this question makes sense. I have a color head but use Ilford filters for contrast. Ilford provide a list of yellow and magenta color head settings with their paper but I get different results with these settings than I do with the filters that slide into the head. I think it sounds easier to use the filters n the color head, so I want to calibrate it but not quite sure how to do this.
If I expose a 31 step wedge using the ilford grade 2 filter for max black min. time, and then dial in the approximate color head filter for a starting point, I assume I am looking to find the filter comb. and exposure time to make a print to match the one made with the Ilford filter. Am I on the right track? Would I then repeat this for other grades?

[Oren Grad]

Unless you are trying to make measurements for technical purposes, or want a head start on matching prints already made with the separate filter set, why do you need to calibrate?

[cowanw]

Point 1. the cyan does not actually provide neutral density. I use to think so but it was pointed out here or on APUG that that was not so. I tested and, strong or weak, blue is blue. Try it and I think you will find the cyan settings are of no effect. (within minor variations in the truethyness of the actual cyan filter.)
Point 2 the values of ilford filters may or may not be written in the bible and they may or may not be what Strand thought grade 2 should be. But that bears no relationship to what you want your picture to look like.
Ilford offers two settings for a variety of different makers. one is the basic filter setting and one is a combo setting to maintain constant times. I use the latter knowing that my old filters are faded and so I start with what I think best and go up or down in contrast as the ilford settings suggest. Fine tune and add a bit of yellow or magenta if you want a 1/4 grade change.
Just don't interchange colour head filters and gel filters. Stick with one.
Exception to the rule.
The old bakelite Kodak or Dupont #5 is much stronger than my colour head, so if I really want contrast I switch to the little under lens gizmo and the magenta #5.
Regards
Bill

[cowanw]

I found the thread
http://www.apug.org/forums/forum37/6...nd-filter.html
See post 9 and post 17
Ignore post 7 and 14
Regards
Bill

[Peter De Smidt]

Check out Paul Butzi's article on how to calibrate a color head to VC BW printing.

[ic-racer]

Here is how to do it: http://www.apug.org/forums/forum41/5...olor-head.html

But why not just use the table Ilford provides?

[coops]

But why not just use the table Ilford provides?[/QUOTE]

All the reading I have done seems to show that they are only an estimate and rarely accurate. I will not get my paper delivered until wed. so I cannot go into the darkroom and see for myself until then.

[coops]

Yes

or you could take your favorite neg and make prints that match the filter set.

Thanks Bob. Am I right in saying that if, for example, I determine that say 15 secs exposure using a #2 ilford filter gets me the desired result with a step wedge, and 10Y 30 M get me the same print using the color head filters, this combination will get me a grade #2 with any paper, aperture combination? I would just need to determine the right exposure time?

[Oren Grad]

Am I right in saying that if, for example, I determine that say 15 secs exposure using a #2 ilford filter gets me the desired result with a step wedge, and 10Y 30 M get me the same print using the color head filters, this combination will get me a grade #2 with any paper, aperture combination? I would just need to determine the right exposure time?

No. Different VC papers respond differently to a given filter set or color head setting. You can see this, for example, if you look at the data sheets for the various Ilford VC papers. Look at the section in the datasheets labeled "ISO Range".

Contrast will also be affected by your choice of paper developer.