From RC test print to FB final print

InExperience · May 31, 2020

Hi Guys,

If I do test strip printers and decide the base time of the print (Dodging and Burning) using a RC paper, the result will be the same for a final print by FB paper? Maintaining same brand and, of course, same kind of paper (classic, cooltone or warmtone).

I didn't experimented that, have you tried it?

Thank you.

Oren Grad · May 31, 2020

InExperience said:
If I do test strip printers and decide the base time of the print (Dodging and Burning) using a RC paper, the result will be the same for a final print by FB paper? Maintaining same brand and, of course, same kind of paper (classic, cooltone or warmtone).

No, the result won't be the same. Within the Ilford product line, which is probably what you're thinking of, the FB and RC versions within each product category have different sensitometric properties, and in particular, quite different characteristic curves (tonal scales).

InExperience · May 31, 2020

Oren Grad said:
No, the result won't be the same. Within the Ilford product line, which is probably what you're thinking of, the FB and RC versions within each product category have different sensitometric properties, and in particular, quite different characteristic curves (tonal scales).

Thank you @Oren Grad for your contribute. Yes that was my idea, but seem doesn't work.

Sorry to open a topic for that, but I had this doubt.

pentaxuser · May 31, 2020

Oren Grad said:
No, the result won't be the same. Within the Ilford product line, which is probably what you're thinking of, the FB and RC versions within each product category have different sensitometric properties, and in particular, quite different characteristic curves (tonal scales).

Oren is this definitely the case? I was reading an article from B&W magazine dated Dec 2007 when it was MGIV of course and it stated that the RC emulsions were the same as FB emulsions for the Multi-grade range Now we have the latest level MG range and it would appear that within this range both RC and FB emulsions are still the samel. I did a quick check on the diagram for the curves and they look the same. The contrast filtration seems to be the same

Of course it has to be the same paper range i.e. not all lford RC and Ilford FB in terms of ranges are the same but within the Multi-grade range it does look as if the emulsions are the same

pentaxuser

Oren Grad · May 31, 2020

pentaxuser said:
Oren is this definitely the case? I was reading an article from B&W magazine dated Dec 2007 when it was MGIV of course and it stated that the RC emulsions were the same as FB emulsions for the Multi-grade range Now we have the latest level MG range and it would appear that within this range both RC and FB emulsions are still the samel. I did a quick check on the diagram for the curves and they look the same. The contrast filtration seems to be the same

Yes, it is definitely the case. I base that not on what Ilford says, but on extensive experience using the papers. But there's plenty of evidence in the data sheets too. The characteristic curves presented by Ilford are pretty crude and can be difficult to compare. But start by comparing the ISO range and ISO speed data and you will see many differences even in the data sheets. The one anomaly I see in the latest MG RC combined data sheet is the RC Warmtone data. Either those data were erroneously transcribed from the FB Wamtone data or the latest coatings have in fact been changed. I can't comment definitively on that until I start a new box from a recent coating, but my guess is that the data are in error.

But if this is important to you, don't take my word for it. Run your own tests. If they look the same to you when treated the same, then that is all that matters for your purposes.

Oren Grad · May 31, 2020

InExperience said:
Sorry to open a topic for that, but I had this doubt.

No need for an apology - it's a perfectly good question! Don't hesitate to ask if there's something you don't understand - that's what we're all here for.

pentaxuser · May 31, 2020

Oren I don't use FB so it is of no direct concern to me.My only concern was to prevent the OP wasting money unnecessarily as was his plan.. Clearly if you can use RC as the test print for a FB result then it makes sense and saves money. Clearly this was allegedly possible when it was MGIV but no longer is the case from your findings

Just as matter or interest was it the same back when it was MGIV or is this erroneous as well and the article I mentioned had it wrong then as well?

pentaxuser

Oren Grad · May 31, 2020

It was not possible when it was MG IV. MG IV RC is radically different from either MG IV FB or MG FB Classic. The tonal scales are just in-your-face, whack-you-over-the-head different. Most importantly, the generation IV RC paper has a "kink" in the middle of its curve, an abrupt decrease in contrast in the upper midtones that just isn't there in the FB papers.

No way for me to know what whoever wrote that article was thinking. I'll just observe that even if the emulsions are "the same" in some theoretical sense, what matters is how they behave when coated on the respective bases, cured, cut, packaged and put to use in the darkroom.

Vaughn · May 31, 2020

You can do as you originally inquired about (using RC to determine printing times for FB paper). Some further test would need to be done -- find out what the exposure difference between the two papers to achieve the exact same tone. For example, if the FB takes 10% more exposure to equal the RC, then do all your preliminary work on RC and then apply the 10% to figure your new time with the FB paper. Then proportionally burn and dodge to match the RC print.

It might save you some FB paper...you will have to decide if the work flow works for you...or is it wasting time rather than paper.

Edited to add: In the long run, using the same paper for test and print is more straight forward...and combining that guy's razor and the KISS principle seems to indicate that, too. But it is a good idea to keep in the back of one's mind for use in other circumstances...say one has a single package of an out-of-manufacture paper and one wants to squeeze every sheet of out it. One can learn an image's burning and dodging needs on a common paper and transfer that pattern to the rare paper. Or do the same on an 8x10 before printing a 16x20.

But in reality -- I always used the same paper and printed 16x20. One or two 5x16 well-placed test strips to get on me on target, then a full size straight work print to look at and study before moving forward with it.

Frank53 · May 31, 2020

I usually don’t mix papers this way, but according to my Heiland split grade controller, difference between MG IV FB (2.5) and MG IV RC (3.0) is half a grade. Times are nearly the same. That could be a starting point if you want to work the way you descibed.
Regards,
Frank

NB23 · May 31, 2020

There is drydown with fb. Don’t ask me how many sheets i’ve lost to this...

The only acceptable practice is to use test sheets from the same box you will be printing. The reason is foremost, because of storage history: you are 100% sure the sheets have been stored/aged together. And by doing so, you anihilate any other probability of error.

NB23 · May 31, 2020

Don’t forget that different developers behave slightly differently with rc vs fb.

Also, rc gets completely developed within 2 minutes while fb takes as much as 5.

No, there is no computable basis to match both papers. Just adding or substracting a percentage is not nearly enough. Because then you have to also convert the development time for each (1:15 for rc would be what, 2:02 for fb? 2:14? Or 1:43?), and then you’ll have to make sure that, let’s say Dektol, pulls out exactly the same amount of information at the same pace, from the same tones, in the same sequebce. I’m not ready to say it’s linear, especially not perfectly linear.

You definitely have to stay on a box-to-box basis. It’s the only way to eliminate all variables, all at once.

MattKing · May 31, 2020

You can learn a lot about a negative by working with it using RC paper.
The lessons you learn can be applied to printing with a different paper.
But probably not directly, one for one.

Vaughn · May 31, 2020

Thanks, Matt -- that is the essence of what all my above words were trying to say.

The reason I went straight to the full 16x20 work print (instead of working with it first as an 8x10 or 11x14) is because I found my images changed depending on their size. Not just grain size or sharpness, but the image itself is often size-dependent. Change the scale and the image may need to printed to a slightly different tonal range and burning/dodging regime.

logan2z · May 31, 2020

Vaughn said:
Thanks, Matt -- that is the essence of what all my above words were trying to say.

The reason I went straight to the full 16x20 work print (instead of working with it first as an 8x10 or 11x14) is because I found my images changed depending on their size. Not just grain size or sharpness, but the image itself is often size-dependent. Change the scale and the image may need to printed to a slightly different tonal range and burning/dodging regime.

Somewhat to my surprise I've found this to be true as well.

MattKing · May 31, 2020

Vaughn said:
The reason I went straight to the full 16x20 work print (instead of working with it first as an 8x10 or 11x14) is because I found my images changed depending on their size. Not just grain size or sharpness, but the image itself is often size-dependent. Change the scale and the image may need to printed to a slightly different tonal range and burning/dodging regime.

Prints do have a subjective character that varies with size and viewing distance.
There probably are differences as well due to the difference in optical performance of the enlarging system at two different magnifications - in particular contrast.

Vaughn · May 31, 2020

I relearned the lesson making pt/pd prints from 120 film negatives. There is a dramatic change in the image printing that small!

InExperience · May 31, 2020

Thank you for all the contributes, now I know that is impossible to compare them.
Even if I wanted to save money, the only things is to be methodic and accurate to value the print strip (either arithmetic or geometric it is).

MattKing · May 31, 2020

I have a suggestion.
Work in the other direction.
Make a print you like on FB paper.
Than do your best to make a matching print on RC. Pay particular attention to matching the surface as close as possible. You may find that RC pearl is closest to un-ferrotyped glossy on FB.
Note the changes you need to incorporate - contrast, exposure times, burning times, dodging times.
If the changes are small, it may be worthwhile to reverse engineer the process, which would allow you to make work prints for evaluation on RC first.

Vaughn · May 31, 2020

And one can explore an image with RC first to see if it is worth going to FB with.
One can print proof sheets on RC, anyway!
Have fun!

MattKing · May 31, 2020

By the way, I print almost exclusively on RC, including my exhibition prints.
I also make extensive use of toning.
RC is different than FB, but the quality of your results depends more on your use of the materials than it does on the differences in the materials.

InExperience · May 31, 2020

A slightly OT, what means OP? (I'm new of the forum).
Do I need to worry? : )

tomkatf · May 31, 2020

Who knows? Variables built in from top to bottom... as everyone has said, you might be able if you do testing and use the same two emulsion batches...

OP is Original Post or Poster...

Pieter12 · May 31, 2020

InExperience said:
A slightly OT, what means OP? (I'm new of the forum).
Do I need to worry? : )

Original Poster, the person who started the thread.

NB23 · May 31, 2020

InExperience said:
A slightly OT, what means OP? (I'm new of the forum).
Do I need to worry? : )

And what is OT?

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