View Full Version : Ilford multigrade contrast differences?
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?
Are these papers both fresh? Older papers generally behave differently, hence the question.
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 :confused:
Jim Noel
8-Oct-2019, 10:14
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
8-Oct-2019, 10:14
or is this an indication something is off?
A recommendation: calibrate paper !
196318
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.info/forum/showthread.php?154485-Darkroom-Printing-CAST-a-powerful-method-for-advanced-curve-control
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 !
196318
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.info/forum/showthread.php?154485-Darkroom-Printing-CAST-a-powerful-method-for-advanced-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 :eek:
I'd still like to hear more experiences if anyone else has worked with Ilford MG both RC and FB. ;)
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
9-Oct-2019, 00:44
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:
196358
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.
> 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/subscription/ps%20paper%20grades.html
Pere Casals
9-Oct-2019, 06:47
> 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.
196359
https://www.ilfordphoto.com/amfile/file/download/file/1748/product/733/
Also see that if we align curves we see a way different sensitivity, so datasheet IMHO has that error :
196360
FB Grades 4 an 5 should have Paper ISO around 100, instead around 200, so ISO 3 in equivalent film ISO.
Pere, look what I wrote. ISO R ratings are not about speed, they are about contrast. Apparently Ilford list the quite light ISO R figure in their data sheet. Again: paper ISO R is not about exposure speed.
Pere Casals
9-Oct-2019, 08:14
> Then there is paper ISO speed chart which for grade 5 indicates 100 for RC and 210 for FB.
Pere, look what I wrote. ISO R ratings are not about speed, they are about contrast. Apparently Ilford list the quite light ISO R figure in their data sheet. Again: paper ISO R is not about exposure speed.
koraks, my reply was about your comment about speed of FB 5 grade, which comes from the error in the datasheet. That 210 should be around 100.
That was not my comment. And grade 5 will evidently never have a higher iso r grade than 100. But maybe you didn't mean grade 5 FB when you spoke of FB 5 grade?
Pere Casals
9-Oct-2019, 10:21
That was not my comment.
It was : https://www.largeformatphotography.info/forum/showthread.php?154589-Ilford-multigrade-contrast-differences&p=1520109&viewfull=1#post1520109
And grade 5 will evidently never have a higher iso r grade than 100. But maybe you didn't mean grade 5 FB when you spoke of FB 5 grade?
No I was speaking about ISO speed , not grade... The error in the datasheet is in the speed...
Pere, look what I wrote. ISO R ratings are not about speed, they are about contrast. Apparently Ilford list the quite light ISO R figure in their data sheet. Again: paper ISO R is not about exposure speed.
Koraks,
As Pere has pointed out, you seemed to miss that there are two ISO charts: ISO Speed and ISO R. It's the ISO Speed that looks strange for grades 4 and 5. I don't see a concerning difference in ISO R between the two papers.
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 for 4-5 than for 00-3, and it's the half.
196359
https://www.ilfordphoto.com/amfile/file/download/file/1748/product/733/
Also see that if we align curves we see a way different sensitivity, so datasheet IMHO has that error :
196360
FB Grades 4 an 5 should have Paper ISO around 100, instead around 200, so ISO 3 in equivalent film ISO.
I always took the fact that grades 4 and 5 needed 2x exposure to be due to the filter factor of the filters themselves, not the speed characteristics of the paper.
If we compare the exposure of RC and FB both with just a grade 5 filter, I think the ISO Speeds are saying that the FB would be one stop faster than RC. This really has nothing to do with the difference between grades 00-3 and 4-5.
If this is true, then you take into account the funny 00 shoulder of RC that you pointed out, combined maybe those effects would explain what I've seen.
Pere Casals
9-Oct-2019, 13:05
I always took the fact that grades 4 and 5 needed 2x exposure to be due to the filter factor of the filters themselves, not the speed characteristics of the paper.
Yes, for sure it would be posible to make a filter set with equal exposure from 00 to 5, IMHO it is good that 4-5 are slower, because 4-5 have a very step gradient and if those filters were faster it would be difficult to burn shadows in a controlled way. Just guessing that this was a factor when designing the filter system... ilford are making VC paper since WWII times, they may have learned something in those 70 years !!!
ic-racer
9-Oct-2019, 19:15
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?
I always make my test strips with paper from the same box from which I will make the final print.
It was : https://www.largeformatphotography.info/forum/showthread.php?154589-Ilford-multigrade-contrast-differences&p=1520109&viewfull=1#post1520109
No I was speaking about ISO speed , not grade... The error in the datasheet is in the speed...
I quoted another post. Read back, you'll find it.
One of the difficulties of establishing absolute speed ratings for paper is the spectrum of the light source used. If you throw a known and identical amount of blue or green light at VC paper, you'll find that the blue emulsion (hard contrast) is generally 2-3 stops faster than the green. This is offset by the low blue amount in normally used incandescent sources. I'm not sure how iso paper speeds relate to light sources, but there may be a problem there.
I did some testing with led light sources; separate leds for blue vs green and known light levels. Hard contrast/blue sensitive emulsion is and ways much faster than the green, but blue output of a regular bulb is much lower than its green output. This creates quite a bit of confusion in this kind of discussion and specific data in the datasheets are usually lacking or minimal.
Pere Casals
10-Oct-2019, 03:54
Hard contrast/blue sensitive emulsion is and ways much faster than the green,
There are not two, but three emulsions (or more in some papers), and all emulsions are blue sensitive, the "green" one is orthocromatic. An intermediate emulsion is also fully blue sensitive but not as green sensitive as the ortho component.
but blue output of a regular bulb is much lower than its green output. This creates quite a bit of confusion in this kind of discussion and specific data in the datasheets are usually lacking or minimal.
ilford shows in the very first page of RC and FB datasheets what are the spectral sensitivities:
196376
Sensitivity peaks in the green, but paper is not sensitive to all green band. Also, as you point, a filament lamp has no flat spectrum. ...additionally, if from LEDs your eyes see the same blue level intensity than with green then you throw much more blue, as our eyes are way less sensitive to blue.
Also vertical scales in the spectral sensitivity are not well specified in the ilford case.
John Layton
12-Oct-2019, 05:23
While Ilford MG Classic and MGWT are now my main papers...I do find that they each change noticeably after about one year, after which each paper is still fully capable of equal (to new paper) results, but that I can not longer use my data with perfect accuracy to make an "equal" print. A bit frustrating (although typically I replenish stocks more frequently than this), but still worth the trouble for these (IMHO) great papers.
Pere Casals
12-Oct-2019, 06:41
I do find that they each change noticeably after about one year
John, cold store it !!!
Modern papers are less stable over time... fortunately we have a solution:
"Paper and film may either be refrigerated or frozen but should first be sealed in plastic bags for protection. Products should be allowed to return to room temperature before opening otherwise condensation will cause damage. Avoid repeated thawing and freezing of films."
https://www.ilfordphoto.com/faqs/
"should first be sealed in plastic bags for protection" IMHO this is Zip Bags with some Silicagel inside, I also throw protective gas inside.
John Layton
12-Oct-2019, 10:25
Appreciated...but kinda tough seeing as most of what I have is either 30x40 and 42" wide rolls. (hmmm...winter is coming - could bury paper in snowbank!)
jose angel
14-Oct-2019, 00:51
... I'd still like to hear more experiences if anyone else has worked with Ilford MG both RC and FB. ;)
My experience, I would say since I realized it, is that the graphics of the manufacturers never worked for me. I think I use Ilford -almost- exclusively since 10-15? years ago.
I get different exposure times and contrasts with different Ilford MG papers; for whatever the reason, in all darkrooms, enlargers and filtering systems (including Ilford ones). I would say that the "classical" rules of contrast and exposure never applied to me.
I check the printing exposure and the degree of contrast with each image and paper box. Each type of paper is different (FB, RC, warmtone, pearl, etc.). BTW, I don't use warm tone paper so often, so I stopped storing it because I found it to be short-lived.
Of course, my processing system is not very scientific (quite the opposite), it is more based on the general aspect of the final print, and I very rarely perform paper tests (maybe the last one was to verify the exposure differences between some RC and FB boxes I had, and I found that they were higher than I though, -I must have the results anywhere-).
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