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Thread: The RC Myth.

  1. #61
    Flotsam's Avatar
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    Quote Originally Posted by Jennifer
    They use the "same" emulsion on the fiber and RC paper. If you make a test print on RC, you will know what to expect on fiber
    All I know is that the image on an exposed sheet of Ilford MG RC snaps up almost as soon as it hits the developer while the Ilford MG FB image doesn't even start to appear for 30 seconds and they have different recommended dev times. Does the base really have that effect on the emulsion?
    That is called grain. It is supposed to be there.
    =Neal W.=

  2. #62
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    That's one of the basic differences between RC and FB. Emergence time on RC is typically 10 seconds, but 30 seconds for fiber. Total development time is typically 1 minute for RC, 2-3 minutes for fiber. There are some exceptions to this, but these times are good in the general case.

    One notable exception is Azo. While the emulsion speed is many times slower than enlarging papers, it develops rapidly, one minute for grade 3, 2 minutes for grade 2.

    We must remember, RC was developed to facilitate mass printing of military recon photos in WWII. I have no idea when it went onto the commercial market. Its strengths are in the greatly reduced processing time and it dries flat. Those strengths are still very viable. I'm not going to spend the processing time trying to crank out two 35-mm rolls of documentary shots for a lawsuit on FB paper. The judge and attorneys ain't gonna care. And they ain't gonna hang in any gallery.

    On the other hand, when the audience is someone who cares, someone who appreciates a good print, fiber is a must.
    Semper Fi & God Bless America
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  3. #63
    Flotsam's Avatar
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    Quote Originally Posted by Alex Hawley
    That's one of the basic differences between RC and FB. Emergence time on RC is typically 10 seconds, but 30 seconds for fiber. Total development time is typically 1 minute for RC, 2-3 minutes for fiber. There are some exceptions to this, but these times are good in the general case.
    Yes, but is that only because of the base difference? Jennifer says that Ilford claims that it is the same emulsion on both papers. It doesn't make sense to me.
    That is called grain. It is supposed to be there.
    =Neal W.=

  4. #64
    Alex Hawley's Avatar
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    Based upon empirical knowledge, I believe it is. Without the emulsion being the same, how else could one work out the exposure and printing on RC, then transfer directly over to fiber with nary a change?
    Semper Fi & God Bless America
    My Photography Blog

  5. #65

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    Quote Originally Posted by Flotsam
    Yes, but is that only because of the base difference? Jennifer says that Ilford claims that it is the same emulsion on both papers. It doesn't make sense to me.
    It can very well be only because of the base difference. With Fiber, the paper is thicker than RC. That means that although more chemicals are soaked up by it, it takes more time for the "soaking" to take effect. With RC, which is Plastic/emulsion/paper/plastic, the soaking is much more immediate, because there is less absorbtion going on.

    I may not have explained this correctly, but it makes sense in my head. In RC, the only thing really soaking up developer is the gelatin (paper itself is very thin). On FB, there is the paper doing it as well. Which may mean that spent developer is not "renewed" in the paper as quickly either. All this could add up to faster development in RC. I believe that the same can be said of film (in that it is similar to RC).

    André

  6. #66
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    Alright. In the interest of furthering human knowledge, I just did an experiment.

    I took a strip of Ilford MG RC and a strip of Ilford MG FB, exposed them to white light, and put a drop of Dektol 1:3 on the surface of each, removing absorbtion as a factor, and watched my my trusty, rusty gralab timer. Here are the results:

    The RC started to show density at 3 seconds and appeared fully black at 10.
    The FB showed tone at 10 secs and didn't appear to max until 30 secs.

    I'm open to explanations but it just don't sound like the same emulsion to me
    That is called grain. It is supposed to be there.
    =Neal W.=

  7. #67

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    Neal, what would we do without you?

    Here's my best guess at this (not that it means much):

    Absorbtion may could still be a factor (gelatin absorbs, paper absorbs through it).
    It isn't likely, though, and 30s sounds reasonable for FB to black out in white light, regardless of how much developer it's in.

    Sooooooo,

    It may not be the same emulsion, but the good folks at Ilford may very well have gone the extra mile to get the papers/emulsions as close as they could, precisely for the purpose of RC to FB conversions.

    I dunno, maybe I'm too naive.

    André

  8. #68

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    Quote Originally Posted by Flotsam
    Alright. In the interest of furthering human knowledge, I just did an experiment.

    I took a strip of Ilford MG RC and a strip of Ilford MG FB, exposed them to white light, and put a drop of Dektol 1:3 on the surface of each, removing absorbtion as a factor, and watched my my trusty, rusty gralab timer. Here are the results:

    The RC started to show density at 3 seconds and appeared fully black at 10.
    The FB showed tone at 10 secs and didn't appear to max until 30 secs.

    I'm open to explanations but it just don't sound like the same emulsion to me
    The only absolute test of whether the emulsions are the same would be to expose a calibrated step tablet to both papers and then to read the dmax and dmin densities as well as plot the curve for both papers.

    If someone wants to contribute some paper (4 sheets of each should suffice) in order to determine the validity of "it's the same emulsion", I will be happy to do the densitometric testing. I would think that those who feel strongly about this would be happy to back up their views on this.

  9. #69

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    I guess there'a difference in use, but you're right, impossible to tell behind glass. Mostly I use fibre, but I do use RC as well, particularly Ilfords Ilfospeed Semimatt. It has a surface to die for and tones like a dream, but does dry-down quite a bit. It's a graded paper. Difficult to get hold of; if you want to try it you should contact Ilford direct, whilst you still can. I just bought a load!
    Peter Hogan.

  10. #70

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    Like so many things, when I started out in photography I thought there were many beleivers in the emperors clothes (those who thought T-grain films lacking in soul and those who thought resin prints inferior). Well, as I grew in experience and my standards were raised, I ate a few hats. They were right on both acounts (IMHO). I now greatly prefer traditional films (but have a soft spot for acros 100 quickloads in Pyro devs) and would never use RC for an exhibition print. ON the second preference, this is because RC glossy is generally too glossy and plasticky for my eye and lacks that glow. I cannot really nail it down, but there is an image depth issue. When I really nail an FB print and it it properly lit it has no real suface and you could walk into it. This never sems to happen on RC for me, it just seems more 2D...I wish it wasnt the case as it is soooooo much easier to work with RC and cheaper and faster....I do however think Ilford warmtone RC to be a cracking paper, which tones really nicely.

    The fact that RC papers are developer incorporated seems to reduce their flexibility somewhat. Thye ultra glossy surface also makes them harder to mount without slight flatness issues causing reflections etc.



 

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