Ilford MG RC Deluxe Paper Curves

Chuck_P said:

Have you ever made a switch from a lower contrast filter to a higher contrast filter, only to see that the higher filter did not effect a change in contrast like you expected......I can tell I have before I acquired my own enlarger. I was using the local photography club enlarger with Kodak under-the-lens filter set......frustrating, as I didn't understand what was going on and I thought a #3 filter was supposed to be a grade 3 contrast........so now I know, that's maybe yes or maybe no.

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Thanks This must seem like I am labouring the point but what you have said above seems to indicate that while Ilford Deluxe does achieve all 5 grades in theory, in practice it does not do this as the grade 3 filter may not achieve a grade 3 print. I am assuming in this that that cause of this is not that you may be using a "worn-out" filter but has other causes.

As I said, I have no experience or real knowledge about the kind of thing you have done with the tests but I am keen to know what practical lessons I need to learn from your conclusions

Is your practical conclusion, from a printing point of view, that a grade 3 filter or indeed any filter may or may not deliver its stated grade to the paper and the causes of this is something we just have to live with.

Does this mean for instance that each set of new Ilford filters may deliver a set of grades that will differ from other new set and that some will deliver all 5 grades while others will not?

Thanks

pentaxuser

Chuck_P said:

But the exposure used to expose for all the filtration settings is based off the lowest contrast filter....or...."dial in the appropriate dichroic filtration to achieve a close approximation of the lowest contrast grade"----Anchell.

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Anchell is wrong here - at least if you are using the two filter method.
It is based on a particular tone. @Nicholas Lindan should probably chime in here.

MattKing said:

It is based on a particular tone. @Nicholas Lindan should probably chime in here.

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I think speed matching the filters is based off the time to achieve a midtone for each filter but not for finding relative RN......I think. There is a test for speed matching filters in his Book, that's different from what I did.

pentaxuser said:

Is your practical conclusion, from a printing point of view, that a grade 3 filter or indeed any filter may or may not deliver its stated grade to the paper and the causes of this is something we just have to live with.

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Can you define what a grade 3 actually is?
There is an ISO standard, I believe, but functionally I think that it is better to approach it as if it is relative, rather than normative.
The OP's investigations show how the results of making changes relate to each other.
The newer version of the Ilford paper improves how regular the spacing is when using the different Ilford filters, or different labelled settings on a variable contrast source like the LPL one.

faberryman said:

Let's say you have a set of Ilford variable contrast filters. They are marked ...2, 2.5, 3, 3.5, 4.... You test them with your standard paper and determine they actually yield ...2.1, 2.6, 2.9, 3.4, 4.1.... Is it your filters, step wedge, or densitometer that is off? How does your approach to printing change?

I guess I fall in the "intuitive" or the "visual judgment" school. I start with a No. 2 filter, see what that looks like, and go from there. If I want more contrast, I try a No.3. If that is not enough, I go to a No. 4. If that is two much, I back it down to a No. 3.5. Of course, if you have a dichroic color head or a variable contrast black and white head, you can fine tune. It is an interative process. The actual contrast grade, be it 3.4, 3.5, or 3.6, does matter, at least to me.

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I expect you mean, "The actual contrast grade, be it 3.4, 3.5, or 3.6, doesn't matter, at least to me."
And I agree with that. But it helps to understand what sort of change will result when you substitute the 3.5 for a 3 filter - it might be more or less than the change that results when you substitute, for example, the 2.5 for a 2 filter.
And of course, if you need to you can adjust that, by doing some split grade printing - dividing the exposure between the 3 and 3.5 filter, or between the 3.5 and 4 filter.
With the variable contrast light source that the OP uses, he can achieve the same results by setting the dials in an intermediate position between the number settings. So if 3.5 is typically a little to contrasty, he can set the dial closer to the position that would be 3.3 if it was marked that way. His curves help him do that in a predictable way.

pentaxuser said:

Is your practical conclusion, from a printing point of view, that a grade 3 filter or indeed any filter may or may not deliver its stated grade to the paper and the causes of this is something we just have to live with.

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Start thinking of the number on the filter as indicating to you just an expected higher contrast on the paper rather than an expected jump to the next contrast grade. If you want to go from filter to filter to incrementally see if your going to be happy with a little more contrast or if you're seeking more contrast....well ok do that......burn through sheets chasing a contrast grade. Remember, your system might not give you any increase at all in contrast...... edit: from one filter to another. Why waist paper on that?

Or, why not know what the relative RN is for the filter your using In your system and go straight to it.

Chuck_P said:

If you want to go from filter to filter to incrementally see if your going to be happy with a little more contrast or if you're seeking more contrast....well ok do that......burn through sheets chasing a contrast grade.

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Actually, I was giving an example of the iterative process. I can usually get to where I need to be pretty quickly. I have been doing it for a while. I don't burn through paper. However, sometimes I make two prints with different contrasts, sleep on it, and see which I prefer the next day (week). I don't think that is a waste of paper.

Do you print with above or below lens filters, or do you use a dichroic color head or variable contrast black and white head? Can you look at a print made with a No. 2 filter, know you need grade 3.7 contrast, dial it in, and you are done?

May or may not be relevant but some years back, I was helping to get a local school darkroom restarted after some years of not being used. Decent equipment (Beseler 23's and 45's) and 6 element glass in 8 different enlargers. We we were chasing our tails, between student miscues, etc but were getting wildly varying contrast results. An initial, cursory look at the optics had told me all was well but after bringing some personal lenses with me, things suddenly behaved more as expected. On more careful inspection, there was a very slight hazing in the stored, school lenses. I didn't think so little (barely discernible) haze that took extreme back-lighting to make out could affect things so much. It taught me to respect the effects of flare.

MattKing said:

I expect you mean, "The actual contrast grade, be it 3.4, 3.5, or 3.6, doesn't matter, at least to me."

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Yes. Thank you. I have corrected my post.

faberryman said:

Actually, I was giving an example of the iterative process. I can usually get to where I need to be pretty quickly. I have been doing it for a while. I don't burn through paper.

Do you print with above or below lens filters, or do you use a dichroic color head or variable contrast black and white head? Can you look at a print made with a No. 2 filter and know you need grade 3.7 contrast, dial it in, and you are done?

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My LPL has a VCCE head, variable contrast constant exposure, so I can dial in the filtration. I don't bother thinking of 1/10 changes in contrast at least not from a global contrast perspective. I do have incremental dial in positions. So a #1 setting gives me a RN of 110 (I know I know, don't forget the flare issue), a low end grade 2 contrast. If I feel i need more, I have all the way through to my #2 setting to that gives me a solid upper end grade 2 contrast. I believe intuition can kick there fairly safely, imo.

I don't think to myself......I need .3 more contrast. I have no intention of testing for relative RNs for such incremental creeping of contrast.

faberryman said:

Yes. Thank you. I have corrected my post.

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Ahhh! I never second guessed your meaning! Good!