Ilford Cooltone Fiber - how to get around a very fast emulsion?

Ghostman · Jan 18, 2016

Has anyone else found that Ilford Cooltone emulsion is very fast? With the same enlarger lens, paper size and aperture, the Warmtone emulsion is considerably slower.

When I print an 8x10 on MGWT the exposures are about 30 seconds and I normally print 1 or 2 stops from wide open (usually f8)

I did some printing on Cooltone Fiber last night and had to stop all the way to the smallest aperture and even then I couldn't get times over 1o-12 seconds. When you're dodging and burning, this can be challenging. I am developing the print in Multigrade Developer.

Can I use an ND filter to slow it down without having to close the aperture?

Many thanks.

megzdad81 · Jan 18, 2016

Use a lower wattage bulb?

Lachlan Young · Jan 18, 2016

Yes - MGWT has an ISO(P) of 100 up to grade 3.5 & 50 at 4-5, MGCT is ISO(P) 250 up to 3.5 & 225 at 4-5, thus about 1.25 stops faster. MGCT is also much contrastier - by about a grade at 4, and at 00 it's not far off MGWT at 1.

I've managed to get MGCT to be well behaved on a MG500 head which is pretty powerful - one trick I've used for an 6x off 35mm is a 105mm lens and a 150mm for 2-3x on 6x7 - ie use the inverse square law to your advantage.

I'd also do a set of tests to see if the diffraction limitations of the lens are visible to you - if not, stop down.

10-12 seconds for a baseline exposure with a couple of dodges sounds about right to me - certainly less maddening than waving your hands on a 200% burn on a neg that has a first exposure of 50s+...

Neal · Jan 18, 2016

Dear Ghostman,

Yes, you can use an neutral density filter. Buy a good one to use below the lens. If your enlarger has a filter drawer, neutral density gel filter sheets can be cut to size and are inexpensive. If your enlarger uses an incandescent bulb you can try a dimmer switch.

Good luck,

Neal Wydra

Ghostman · Jan 18, 2016

megzdad81 said:
Use a lower wattage bulb?

I have a Multigrade 500 enlarger. I'll have to look into this as an option. Thanks.

Lachlan Young said:
Yes - MGWT has an ISO(P) of 100 up to grade 3.5 & 50 at 4-5, MGCT is ISO(P) 250 up to 3.5 & 225 at 4-5, thus about 1.25 stops faster. MGCT is also much contrastier - by about a grade at 4, and at 00 it's not far off MGWT at 1.

I've managed to get MGCT to be well behaved on a MG500 head which is pretty powerful - one trick I've used for an 6x off 35mm is a 105mm lens and a 150mm for 2-3x on 6x7 - ie use the inverse square law to your advantage.

I'd also do a set of tests to see if the diffraction limitations of the lens are visible to you - if not, stop down.

10-12 seconds for a baseline exposure with a couple of dodges sounds about right to me - certainly less maddening than waving your hands on a 200% burn on a neg that has a first exposure of 50s+...

Thanks very much Lachlan, this is very helpful. I also sometimes use a 150mm lens for printing 6X7. My print in question was a 6X7.

Neal said:
Dear Ghostman,

Yes, you can use an neutral density filter. Buy a good one to use below the lens. If your enlarger has a filter drawer, neutral density gel filter sheets can be cut to size and are inexpensive. If your enlarger uses an incandescent bulb you can try a dimmer switch.

Good luck,

Neal Wydra

Many thanks. I will try an ND.

sandholm · Jan 18, 2016

Go the ND way, I use a filter below the lens and it works perfect.
( and in compare to the dimmer and lower light bulb, you can remove the filter to check your focus and then swing it back)

Lachlan Young · Jan 18, 2016

Don't use a dimmer with VC papers - a dimmer will change the colour of the lamp.

Roger Cole · Jan 18, 2016

I haven't tried MGCT yet but the first thing that occurred to me was combining equal units YMC color printing filters in my drawer with the VC filter if necessary. They might not be totally accurate and so might affect the contrast but probably not very much and could be worked around by adjusting which VC filter was used. But I seem to be unusual these days in having a full set of CP filters for my condenser enlarger and having used them quite successfully for RA4 and Ilfochrome once upon a time.

Sent from my iPhone using Tapatalk and 100% recycled electrons - because I care.

StephenT · Jan 18, 2016

I believe adding Cyan filtration acts as a neutral density filter. Dial in 100 units and see what effect it has and please report back.

MattKing · Jan 18, 2016

StephenT said:
I believe adding Cyan filtration acts as a neutral density filter. Dial in 100 units and see what effect it has and please report back.

Theoretically, for printing on paper that has sensitivity to blue and green light, to get the neutral density result you need to add equal amounts of magenta and yellow filtration. If you are working with panchromatic materials, you also need to add the same amount of cyan.

It may be the case that adding cyan filtration has an indirect benefit of cutting the light intensity, because no filter is perfectly efficient, and there is always some loss of light intensity when a filter comes into play, even with very efficient dichroic filters.

With an Ilford Multigrade 500 head, you don't have the option of adding equal amounts of different colours of filtration - that is not how the control works.

DREW WILEY · Jan 18, 2016

Both Cooltone and Classic expose considerably faster than Warmtone, roughly one stop different.

nworth · Jan 18, 2016

Neal said:
Dear Ghostman,

Yes, you can use an neutral density filter. Buy a good one to use below the lens. If your enlarger has a filter drawer, neutral density gel filter sheets can be cut to size and are inexpensive. If your enlarger uses an incandescent bulb you can try a dimmer switch.

Good luck,

Neal Wydra

A couple of alternatives for use in the filter drawer: You can print a neutral density filter on a high resolution ink jet or laser printer. It will have dots, but they will be out of focus and averaged out in when used in the filter drawer. You can use a trio of equal density CC filters that add up to neutral, e.g. CC50Y, CC50M, and CC50C (or CC50R and CC50C) add up to CC50ND. The amount of neutral density you can get from CC filters is limited. You can do the same thing with the filters in a dichro head. If you do not mind the diffusion, you can use a piece of diffusion plastic or frosted mylar in the filter drawer. This cuts the light down quite a lot.

I have one small enlarger that puts out too much light for most uses, and I opted for a high quality ND0.6 filter below the lens to give me a two stop attenuation. It works well. But I have used all the filter drawer methods from time to time, also with good results.

JW PHOTO · Jan 18, 2016

MattKing said:
Theoretically, for printing on paper that has sensitivity to blue and green light, to get the neutral density result you need to add equal amounts of magenta and yellow filtration. If you are working with panchromatic materials, you also need to add the same amount of cyan.

It may be the case that adding cyan filtration has an indirect benefit of cutting the light intensity, because no filter is perfectly efficient, and there is always some loss of light intensity when a filter comes into play, even with very efficient dichroic filters.

With an Ilford Multigrade 500 head, you don't have the option of adding equal amounts of different colours of filtration - that is not how the control works.

Matt,
I use an Ilford Multigrade 400 head, but haven't tried those papers yet. What would you use to "slow things down" when using these papers with the Multigrade 400 or 500 heads?

MattKing · Jan 18, 2016

JW PHOTO said:
Matt,
I use an Ilford Multigrade 400 head, but haven't tried those papers yet. What would you use to "slow things down" when using these papers with the Multigrade 400 or 500 heads?

I too use a 400 head.

Using the 4x5 mixing box with smaller formats helps.

Otherwise, the only really useful technique is to use neutral density.

Changing to a longer lens doesn't really help directly, because intensity at the easel is a function of magnification, not just lens to paper distance. Longer lenses do, however, often offer a smaller minimum aperture (e.g. f/32 instead of f/22) so that can help a little, if you can put up with an increased amount of diffraction.

EDIT: In addition, in some cases it can help to use split contrast grade printing, because it can often be easier to split up your dodges and burns between the two grades.

JW PHOTO · Jan 18, 2016

MattKing said:
I too use a 400 head.

Using the 4x5 mixing box with smaller formats helps.

Otherwise, the only really useful technique is to use neutral density.

Changing to a longer lens doesn't really help directly, because intensity at the easel is a function of magnification, not just lens to paper distance. Longer lenses do, however, often offer a smaller minimum aperture (e.g. f/32 instead of f/22) so that can help a little, if you can put up with an increased amount of diffraction.

EDIT: In addition, in some cases it can help to use split contrast grade printing, because it can often be easier to split up your dodges and burns between the two grades.

I've been using the 4x5 mixing box for all my smaller formats except 35mm for which I have a separate Focomat Ic enlarger with the 400HS head. I don't like using real small apertures so I guess it's split grade printing and/or an ND filter. I really don't mind faster paper as long as there is no burning or dodging to be done.

Loren Sattler · Jan 18, 2016

"Don't use a dimmer with VC papers - a dimmer will change the colour of the lamp."

Lachlan, please explain the consequence of a color change. I recently started using a Leitz iC enlarger with a 150 watt bulb that is too bright for small prints on RC paper. I put a dimmer switch in the line and it appears to work well. Am I missing something in print quality or....??

MattKing · Jan 18, 2016

A dimmer will change the colour temperature of the light emitted by the light source.

Which will in turn change the contrast response of the paper.

Which will make it hard to get repeatable results.

Ilford Cooltone Fiber - how to get around a very fast emulsion?

Ghostman

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