Ilford multigrade contrast differences?

[gnd2]

I've been using Ilford Multigrade IV RC Deluxe pearl paper successfully for a while now and finally got some FB classic matte to try out. The FB contrast seems to be much higher than the RC.

I'm enlarging a 4x5 FP4 negative to 8x10. The process is essentially the same for both RC and FB, using the recommended times by Ilford (obviously using the longer times for FB) with Multigrade developer and Rapid Fixer.

I'm doing split grade printing using a Durst CLS450 color head, so I'm looking at the contrast adjustments in terms of the low contrast and high contrast exposures.

With RC, the high contrast exposure was a little more than the low contrast, maybe 1/2 stop difference. I'm guessing that would be close to a 2.5 grade so I figured the negative was decent (negative also looks reasonable to my eye).

I re-ran the test strips for FB, the low contrast exposure remained very close to what I got with RC, but the high contrast exposure is less than half the RC exposure for about the same shadow detail.

This difference took me by surprise. I didn't expect them to be identical, but thought they'd be closer. Is it normal to see this much variation between papers or is this an indication something is off?

[koraks]

Are these papers both fresh? Older papers generally behave differently, hence the question.

[gnd2]

Yes, shipped from B&H end of August and early September.

Running the numbers through my head again this morning I think the FB high contrast exposure is closer to 1/4 the RC exposure, about 2 stops less. Seems an awfully large difference

[Jim Noel]

IIRC the emulsions for the RC Pearl, and the fibre matte are two different animals. My experience with them was a longer, more pliant scale with fibre, and a shorter,more contrasty scale for RC. I have not used RC in many years so my memories are based on older materials. CHeck the graphs for each "paper" on the Ilford site.

[Pere Casals]

or is this an indication something is off?

A recommendation: calibrate paper !




You don't even need a densitometer. Just get an Stouffer T2115 Transmission 21-Step , this is $8.

You may also get a Reflective wedge, R1215, also $8, for reference but not necessary.


You make contact copies and you see what happens. Now you may have several interactions between exposure, color head and paper kind.

Just make contact copies of the T2115 and see how many steps (patch count) it takes going from black to full white for each grade and for each paper, in that way you will have a consistent workflow across diffrent papers and situations.

Remember that gardes 4, 4.5 and 5 do require x2 the exposure for the light greys.

In the future you may plot graphs, etc that are explained in Beyond The Zone System Book, but for now just by counting how many patches you have between full black and full white you may compare paper vs grade combinations.


You may also find this way interesting: https://www.largeformatphotography.i...-curve-control

[gnd2]

IIRC the emulsions for the RC Pearl, and the fibre matte are two different animals. My experience with them was a longer, more pliant scale with fibre, and a shorter,more contrasty scale for RC. I have not used RC in many years so my memories are based on older materials. CHeck the graphs for each "paper" on the Ilford site.

Your experience seems to be the opposite of mine.
I'm not sure how to compare the graphs, but there's a comment on the RC data sheet right before the plots stating the curves are "broadly similar" between different MG papers, whatever that means. Otherwise, looking at the graphs I would expect the results to be closer than they are.

Then there is paper ISO speed chart which for grade 5 indicates 100 for RC and 210 for FB. Would this suggest that the high contrast layer of FB is about twice as fast as RC? ISO-R values don't seem that different.

A recommendation: calibrate paper !




You don't even need a densitometer. Just get an Stouffer T2115 Transmission 21-Step , this is $8.

You may also get a Reflective wedge, R1215, also $8, for reference but not necessary.


You make contact copies and you see what happens. Now you may have several interactions between exposure, color head and paper kind.

Just make contact copies of the T2115 and see how many steps (patch count) it takes going from black to full white for each grade and for each paper, in that way you will have a consistent workflow across diffrent papers and situations.

Remember that gardes 4, 4.5 and 5 do require x2 the exposure for the light greys.

In the future you may plot graphs, etc that are explained in Beyond The Zone System Book, but for now just by counting how many patches you have between full black and full white you may compare paper vs grade combinations.


You may also find this way interesting: https://www.largeformatphotography.i...-curve-control

I hadn't picked up a step wedge yet since I've been happy with my results up till now. I suspect it will simply be another quantification of what I'm already seeing - this FB is significantly more contrasty than this RC. I can adjust to it, but the question is, is this normal?

I'll pick one up next chance I get, probably just get another box of paper too. Maybe glossy this time. I hate RC glossy but I don't think I was fully prepared for just how matte FB matte really is

I'd still like to hear more experiences if anyone else has worked with Ilford MG both RC and FB.

[cowanw]

Yes fibre glossy comes out quite nicely if you do not ferrotype it.
And I use these and also think the RC is more contrasty, but then it's glossy. It is also a different speed.

[Pere Casals]

this FB is significantly more contrasty than this RC. I can adjust to it, but the question is, is this normal?

Main difference is in 00 grade of the RC, the 00 RC grade has a weird shoulder (in papers the shoulder contains the shadows), being more difficult to reach full blacks with it.

See the 00 RC shoulder pointed:



RC 00 has the same contrast than 0 for the mids, but it's less strong with shadows, like if shadows had been dodged 50% of the exposure, which is a lot for the same mids.

Perhaps this is what you notice... FB papers do not have that behaviour in Grade 00.

With 0 grade (and up) I find a similar behaviour, RC vs FB

_____

For the rest RC and FB CLASSIC papers may have half a grade shifts for the same grades, depending on specific paper, but not more. Warm vs Cold tone (and etc) have different halides so a perfect match is not there, but we have a close match.

[koraks]

> Then there is paper ISO speed chart which for grade 5 indicates 100 for RC and 210 for FB. Would this suggest that the high contrast layer of FB is about twice as fast as RC? ISO-R values don't seem that different.
No, ISO-R is a measure of contrast, not of speed. I think it's something like 100x the log difference between negative densities that produce white vs black. So ISO R 100 is a dlog difference of 1.0 which is roughly 3 stops, so a fairly average/normal grade. See here: http://www.rogerandfrances.com/subsc...%20grades.html

[Pere Casals]

> Then there is paper ISO speed chart which for grade 5 indicates 100 for RC and 210 for FB.

Koraks, I guess this is a remarkable error in the FB datasheet, first text mentions that 4 and 5 grades require double exposure, and because of that 4-5 curves are in another plot, if you check the scales in the curves it also shows that sensitivity is the half.

What is clear to me from my calibrations is that 4-5 grades in the FB require x2 exposure, I saw that pitfall in those tables long ago, when I was making the calibrations... FB datasheets same speed dor 4-5 than for 00-3, and it's the half.




https://www.ilfordphoto.com/amfile/f...8/product/733/


Also see that if we align curves we see a way different sensitivity, so datasheet IMHO has that error :




FB Grades 4 an 5 should have Paper ISO around 100, instead around 200, so ISO 3 in equivalent film ISO.