Paper tests

[JPJackson]

After reading here about split-filter printing and discovering that the enlarger light source "color" has definite effects on the response of filter use with VC paper, I ran some further tests. Back in Feb i tested MGFB(cool tone) with my Ilford filter set. The curves are attached. It was a mystery to me why there are only grade 2 and 3 response curves.

A couple of days ago i retested MGFBCT with no filter and a #58 wratten filter (glass) and was delighted to see a grade 4 and 0 response curve. The curves are attached for this test too. There are also curves from some MGFB dated 1995, (MGFBV).

My enlarger has an Aristo T-12 head (cold light) and now i understand why the Ilford filters were not giving me the results expected.
Developer was Dektol 1:2 for 2 minutes (69F).

Now, on with split-filter printing.

Thank you APUG for the freely shared knowledge!

 

[bernard_L]

and now i understand why the Ilford filters were not giving me the results expected

Nice results and good for you! But if you understand the why, could you share? Is it that the Ilford multigrade filters of soft grades have leaks in the UV, where your cold light source (but not an incandescent lamp) emits significant radiation?

 

[JPJackson]

According to an article by Steve Anchell both Ilford and Kodak Variable contrast filters are designed for tungsten light sources. That was big news to me.

 

[ic-racer]

It was a mystery to me why there are only grade 2 and 3 response curves.

Did you read the datasheet before performing the tests? http://www.ilfordphoto.com/Webfiles/2006130201152306.pdf

 

[JPJackson]

Did you read the datasheet before performing the tests? http://www.ilfordphoto.com/Webfiles/2006130201152306.pdf

Thanks for the data sheet. I did not have it, my filters are 1992 vintage and the data sheet from them is missing.

I am just getting back into this after a twenty year break. So much to learn and so much forgotten.

 

[MartinP]

I had the strong impression that cold-light heads have never actually been recommended for multi-contrast printing, because they do not produce the necessary amounts of green and blue light, as required for the multi-contrast paper to work.

Filters that are twenty-five years old may also be for a previous version of Ilford Multigrade papers - there have been a few 'editions' of the products. Being that old, the dyes may well also have been affected by light and time.

Have you recently tried printing on fixed-grade papers, as intended for the light-source you have? That may give more predictable results, without any odd effects from extra UV. Were you using the recommended extra yellow filtration, along with the multicontrast filters?

 

[ic-racer]

Thanks for the data sheet. I did not have it, my filters are 1992 vintage and the data sheet from them is missing.

I am just getting back into this after a twenty year break. So much to learn and so much forgotten.

The datasheet mentions that the Aristo bulb W-42 (which you likely have in your T-12 head) can have improved spread of contrast grades with additional yellow filtration. I used a W-42 lamp for 8x10 printing a few years with additional yellow and the Ilford filters with success. You can upgrade your Aristo lamp also. The new owner of my Aristo head replaced the W45 with a new lamp made by Aristo.

 

[JPJackson]

I had the strong impression that cold-light heads have never actually been recommended for multi-contrast printing, because they do not produce the necessary amounts of green and blue light, as required for the multi-contrast paper to work.

Filters that are twenty-five years old may also be for a previous version of Ilford Multigrade papers - there have been a few 'editions' of the products. Being that old, the dyes may well also have been affected by light and time.

Have you recently tried printing on fixed-grade papers, as intended for the light-source you have? That may give more predictable results, without any odd effects from extra UV. Were you using the recommended extra yellow filtration, along with the multicontrast filters?

I have not purchased any fresh graded paper yet but intend doing so. Mostly it has been contact printing using a 75W daylight bulb and old grade 3 AZO or contact prints using MGFB and the Omega F enlarger. The printing results have been ok; it was the paper test using the MG filters results that didn't make sense to me - due to my ignorance of the "color" aspect of the enlarger light source. I think using addition yellow filtration with the MG filters may be even slower than the 2.5 stop speed loss seen with the #58 green filter vs "no filter"; will just have to try it and see.

My plan is to expose the MGFB first with "no filter" and finish the highlights with the # 58green filter.

 

[JPJackson]

The datasheet mentions that the Aristo bulb W-42 (which you likely have in your T-12 head) can have improved spread of contrast grades with additional yellow filtration. I used a W-42 lamp for 8x10 printing a few years with additional yellow and the Ilford filters with success. You can upgrade your Aristo lamp also. The new owner of my Aristo head replaced the W45 with a new lamp made by Aristo.

Thank you for this information as well; you seem to have been down this trail before.

It is nice to know that Aristo is still around.

 

[Gerald C Koch]

Thanks for the data sheet. I did not have it, my filters are 1992 vintage and the data sheet from them is missing.

Another consideration filters fade and yours are more than 20 years old.

 

[JPJackson]

Another consideration filters fade and yours are more than 20 years old.

Yes, it is time to retool.
Yesterday I made proof prints using only the #58 filter and was happy to see obvious low contrast.
Now to work on the split between "no filter" and the #58.
The cold light heads I bought back in the 80s were "silver bullets"; I am still astounded at missing the fact that the poly-contrast and multi grade filters were designed for the light sources I replaced. Graded papers did print well and some fresh paper is on the way.

 

[fotch]

Another consideration filters fade and yours are more than 20 years old.

Do the filters fade even if not used, just stored?

 

[Gerald C Koch]

Do the filters fade even if not used, just stored?

Depends on the nature of the filter and the dyes used.

 

[RPC]

I have Wratten filters nearly 30 years old (stored in the dark, seldom used) that show no signs of fading, so some can hold up.

 

[Patrick Robert James]

Jut throwing this out there but in place of the MC filters I have used 47 ad 58 filters with enlargers that didn't have VC filtration built in. I have read that the 47 filter produces more contrast than MC filters with some papers, but I never tested it. I have kept a set of under the lens Ilford MC filters with two of them replaced with 47 and 58 gels. I keep them around in case I ever run across a Leitz Focotar that has my name on it.

If you are printing with VC paper, I think it is best to use a tungsten source. The cold light heads are old technology meant for graded paper that has had it's day at this point. If you don't want to use the condensers with your Omega, there is a guy who makes diffusion disks. Glenview is the website I think. Best of both worlds for you.

Good luck!

 

[JPJackson]

FYI the new papers (MG Classic and MG Cooltone) no longer have the bumps/discontinuities in the lowest grades.

Thank you. I made my first split-filter contact print yesterday using the Aristo T-12. The image is posted in the Critique Gallery. I enjoy the tonality of the MGFB Cool tone very much.

 

[JPJackson]

I modified my lamphouse (Omega 5x7 Omegalite "saucer") recently and used new Ilford filters under the lens to check out its performance with MGIV FB paper. I also tested it with 47B gel and 58 glass filters. The LEDs were 8500K. Then I plotted the curves that I made with a Stouffer 31-step. I shifted all the curves to a common reflection density of .09 (Zone VIII) to compare the change of slopes more easily. My similar tests with Ilford's newer paper (MG Classic - not Cooltone) are not yet completed, but I understand that in addition to being a somewhat faster paper the separation between curves is now more uniform as well. BTW, the behavior of the "softer" curves is explained very well in the following article:

http://www.darkroomautomation.com/support/appnotevcworkings.pdf

Thank you for this article and the feed back; looking forward to your paper test results. Your curves look more like what i expected to see. Maybe new filters are in order for me.

 

[Arklatexian]

My filters are stored in a drawer in a darkroom which is pitch dark when no one is in there working and I keep the darkroom at 68F/20C all year and yes they do fade with time.....Regards!