Paper speeds

DWThomas · Oct 18, 2006

OK, I just celebrated Tuesday by printing some black & white shots from my recently acquired SQ-A. This is after a brief darkroom hiatus of -- oh -- 25 years! I vaguely recall needing exposures of half a minute or maybe more back when. And today, I was down around 4 or 5 seconds at apertures of f22 to f32; felt like I was running out of control.

Back when, I used a rather crude homemade enlarger, and now I have a new to me condenser enlarger, an Omega B-8, and I have the correct mid-size supplemental condenser lens to go with the Nikkor 80mm f5.6, so I suppose I'm really optimized. Actually, it occurs to me that one factor could be less magnification required for generating 8 x 8 inch prints from 6 x 6 cm negatives compared with 35 mm. At any rate, I feel like I should be looking for a neutral density filter. :confused: (Or a 25 or 30 watt versus 75 for the PH111 enlarger lamp.)

Today's tries were on Oriental Seagull and on Ilford MGIV -- anybody have any idea how these compare in speed/sensitivity with the "standards" of yore -- like Kodabromide or Polycontrast?

All in all, I'm pretty happy with what I'm seeing, just a little surprised at what feels like instantaneous exposures on the raggy lower limit of my (also crude) homemade enlarger timer.

DaveT

kb244 · Oct 18, 2006

Polycontrast III RC when I shot it in the back of my Crown Graphic, appeared to be roughly ISO 12. It was actually the first 'emulsion' I shot in the back of my 4x5 as opposed to just shooting straight film.

Far as enlarger wattage, you check the condensor perhaps?

Kevin Caulfield · Oct 18, 2006

Even if you had no filtration at all, those times seem way too short.

kb244 · Oct 18, 2006

Kevin Caulfield said:
Even if you had no filtration at all, those times seem way too short.

Ditto, as even on my beseler 23C with a 75Watt bulb, I can get 10 to 20 seconds from f/8-f/11.

seadrive · Oct 18, 2006

If you want longer exposure times, try printing-out paper. 15 minutes in the bright noonday sun!

4 or 5 seconds at f/32 seems unusual...

Gerald Koch · Oct 18, 2006

Years ago, Baumann, the then manufacturer of Acufine and Diafine used to publish a set of paper speeds for their print developer, Printofine. If you could get a copy of this publication it might be helpful.

Bob F. · Oct 18, 2006

Can't compare with past papers but MGIV is one of the fastest current papers - only Kentmere Fineprint is faster that I have tried. Under 5 seconds at f/32 seems rather short, but then, I've always used diffusion/colour enlargers and they give out less light per watt.

My Durst has a 250W halogen and does not come close to that - especially once I dial in some contrast filtration. Even postcards from 35mm take around 10-20 seconds @ f/11, Using VC filters might give you another three or five seconds to play with, but even then it looks like a 2 stop ND might be the best way to go.

Have fun, Bob.

removed account4 · Oct 18, 2006

i am not sure about paper speeds.
the paper companies used to give asa's,
but their paper-speeds were relative to paper,
and not relative to asa of film ...

i never tested asa's of the papers you mention ( 25 years ago )
but in the 90s i made long list of papers i had on hand and
tested it all so i could get asa's relative to film ---
all so i could meter-read light for making paper negatives ..

the lion's share were between asa 3 + 6 with a few developer-incoroporated
rc papers that were about asa 12 --
Photo Engineer has also suggested a few times that some paper has an asa about 25 ...

could your film be thin?
i ask mainly because when i bought a cold light head and began printing
from negatives i had formerly printed through a condensor,
my times were so fast i could barely make a print.
i had to purchase a "dimmer switch" from aristo, until i began to use negatives suited
for a cold light source.

DWThomas · Oct 18, 2006

10 to 20 seconds from f/8-f/11.

Yeah, that sounds more like what I was expecting. It never crossed my mind I'd ever see an enlarger with too much light output! This AM I actually tried an A-B measurement with an Ilford EM10 using the existing bulb and a new one I bought for a spare. The new one was dimmer, but within half a stop. I've seen household bulbs get a twisted filament and put out about 4x light once or twice -- but usually only for a very short time before they start emitting darkness.

Maybe when I get some time again I'll change it over for 35 mm and print a few of my shots from Argust 6th. Be a chance to see if it acts any different. I sorta take back my comment about 35 mm vs MF magnifications in the original post though. Now that I'm awake, it seems like that would not apply, assuming one uses condensors and lens matched to the format being enlarged.

I'm not really concerned about an ISO speed for the paper, I just wondered if paper had gotten as much faster as film has in the past 20 years! (I shudder to think of putting some ISO 800 stuff thru my Brownie Target!)

I should check my line voltage -- my local power folks have been a little generous lately. Somewhere I have a 100 VA constant voltage transformer, I should explore the dark corners and find that.

OK, enough thinking out loud for now, thanks for the comments.

Dave

DWThomas · Oct 18, 2006

could your film be thin?

Well, I suppose that's another area to contemplate, although I have to wonder about two or three stops thin. I admit to concentrating more on general handling of this larger hunk of camera and finding film back light leaks than exposure. I guess a little more careful investigation of my "personal film speed" might be in order. I thought the negs generally looked pretty good, but I suspect "good" is not a universally agreed standard. What the hey -- an excuse to go out and take more pictures!

Dave

Jim Jones · Oct 18, 2006

Long ago Kodak and perhaps other paper makers gave the ANSI paper speeds of their products. These speeds were derived from ANSI Standard PH 2.2-1972. I haven't found that publication yet. A 1982 Kodak publication gives the following information. The ANSI speed of AZO paper was from 8 to 2, depending on contrast. Kodabromide was from 500 to 125, and Medalist from 160 to 200, again depending on contrast. Polycontrast was 160 without a PC filter, and from 100 to 50 with filter. Polycontrast Rapid was 320 without filter, and from 250 to 64 with filter. Ilford also gives a speed rating of photo paper in a 1999 publication without identifying it as the ANSI rating. Their numbers seem to be lower.

Photo Engineer · Oct 18, 2006

If you want a true ISO speed of any paper product (or a very close approximation), simply cut some 4x5 sheets and expose a MacBeth color checker with the sheets at different ISO speed settings on your camera, and then process the sheets of paper.

The one in which the neutral scale is centered, with Dmin at one end and Dmax at the other will give you a very very accurate picture of speed.

Using this method, Ilford MGIV gives an ortho response with an ISO of 25, and in which different colors have different contrasts. I have posted an image of that elsewhere IIRC.

PE

Helen B · Oct 18, 2006

The current international standard for B&W paper speeds is ISO 6846–1992. ANSI are the lead organisation for the technical committee that set photographic standards (TC 42).

The standard also sets ISO range - which is approximately equal to 100x the density range that the paper can handle. A paper with a range of R70 will match a negative with a density range of 0.70.

From Ilford (hopefully Simon or PE will correct me if I have this all wrong):
ISO speed
The speed of MULTIGRADE IV FB Fiber depends
on the filtration used during exposure.
MULTIGRADE IV FB Fiber unfiltered, has a paper
speed of ISO P500.

MULTIGRADE IV FB Fiber paper and
MULTIGRADE filters
Filter 00 0 1 2 3 4 5
Speed (P) 200 –––––––––––––– 200 100 100

ISO range
MULTIGRADE IV FB Fiber paper and
MULTIGRADE filters
Filter 00 0 1 2 3 4 5
Range (R) 170 150 130 100 80 60 40

Oriental VC-FB
Speed: Same ballpark as MG IV.
Range: R160 for #0 filter, falling to R60 with #5.

The Oriental and Ilford Photo websites have full info on all their paper speeds and ranges - Ilford more info than Oriental.

As usual, Kodak have the most comprehensive info:

The ISO speeds and ranges for Polycontrast are here and the Kodabrome info is here.

Best,
Helen

Photo Engineer · Oct 18, 2006

Helen;

I was relating Paper ISO speed to Film ISO speed.

Otherwise, there is no relationship.

PE

Helen B · Oct 18, 2006

Photo Engineer said:
Helen;

I was relating Paper ISO speed to Film ISO speed.

Otherwise, there is no relationship.

PE

I realised that - sorry if I gave any other impression. I was just adding to Jim's post on ANSI paper speeds.

Best,
Helen

dancqu · Oct 19, 2006

DWThomas said:
...an Omega B-8, and I have the correct mid-size
supplemental condenser lens to go with the Nikkor
80mm f5.6, so I suppose I'm really optimized. DaveT

Try being less optimized. You've more condensation than
needed for your purposes. Pull that supplemental and spread
the light source to fit 6x9 or any smaller format at reduced
light intensity.

BTW, I've two B8s. Use one for all my work. I've now
a 105mm Nikkor installed so that the small prints I make
don't put the lens so near the easel. No more than 105mm
though. If more you'll run out of condensed light when
making small prints. Dan

DWThomas · Oct 20, 2006

Try being less optimized. You've more condensation than
needed for your purposes. Pull that supplemental and spread
the light source to fit 6x9 or any smaller format at reduced
light intensity.

That made sense, so I gave it a try, using a thin gray test negative and the EM10 monitor. To my surprise (and slight confusion), there was less than a half stop difference with and without the supplemental. Still using the 80 mm lens, the illumination appeared a little less even across the field without the supplemental glass.

My original question certainly provoked an interesting stream of information, my thanks to the responders. I'm gratified to see that someone is actually using a B8 successfully -- they don't show up much on that auction site -- made me wonder if it was a disaster or I had one of the only three ever made. I ended up making a 1.5 inch lens cone for the 80 mm, so I'm still keeping an eye open for the authenticke 1.5 and 2 inch cones. If I get the latter, I'll eventually try to score a 105 mm lens.

When I get some time I think I'll cut a piece of diffuser material to fit the lamphouse filter drawer and see what that does. I suppose I can also try some bracketed exposures and maybe a little extra development time on a roll or three of film and see what that can tell me about my negative production process. It's been years since I did any of this (and I may not have known what I was doing then!)

I just got back a roll of Provia 100F taken for test purposes with this camera and using my new Digisix meter. It looked alarmingly good, so I must be close.

DaveT

gainer · Oct 20, 2006

If you feel the need of a dimmer switch, your local hardware will have one you can mount in a box. My power company was jacking up the line voltage to the allowable limit, over 125, causing early burnout of expensive bulbs. I connected a filament transformer's priary and secondary so as to make a voltage reducing autotransformer. If you understand all that, you can get a suitable transformer from Radio Shack along with a box to put it in and reduce the out put by the amount of the filament voltage, saving lots on bulbs.

The power company's excuse was that otherwise, people on the end of the line would have low voltage. When I took my requisite E. E. course, we were taught that power line transformers had taps to ovrcome that problem. I think they actually discovered that high voltage meant high wattage and increased income.

Markok765 · Oct 20, 2006

Bob F. said:
Can't compare with past papers but MGIV is one of the fastest current papers - only Kentmere Fineprint is faster that I have tried. .

In my testing, most agfa MCC papers are 2x as fast as MGIV

DWThomas · Oct 20, 2006

If you feel the need of a dimmer switch

Yeah, I could easily do that. I suppose at some level, the color temperature reduction might confuse VC paper, but I probably wouldn't go down that far. I did a basement exploration and located the constant voltage transformer I own. It's actually 150 VA, spec'd for 118 volt output, so should be quite adequate. I measured line voltage with and without, but my DVM is apparently befuddled by the typically raggy output waveform of those CV transformers. The light level was slightly reduced on the CV unit, but only by a fraction of a stop.

Actually, if I just make bigger prints, the problem will go away! I was trying to start slow and cheap with 8 x 8 inches on 8x10 paper.

The bulb is about the size of a stoplight bulb, bayonet base, painted white -- maybe I could dip a glove compartment light bulb in white paint and use a transformer -- enh, just kidding!

DaveT

dancqu · Oct 20, 2006

DWThomas said:
That made sense, so I gave it a try ...
DaveT

Less than half a stop difference. Off hand less than expected
given the area of coverage. Same every thing else I'd think
a more even illumination. Perhaps only you and your
EM-10 will know. I also have an EM-10 and use it.

I think you will appreciate the enlarger higher on the
column. The 105mm will do that and make for an even
greater reduction in light intensity. I test and proof
as small as 3 x 4 two up on 5 x 7.

Omega started with the 35mm A series back in the late
30s. They have had or still do have an A, B, C, D, and,
IIRC, E and F series; 35mm, 120, 3 1/4 x 4 1/4, 4 x 5,
5 x 7, and 8 x 10. The old Ds are very much in use
and some precede their junior B version. I worked
with the D2 for years. I own a very rare C. Dan

Nicholas Lindan · Nov 22, 2006

A graph of paper speeds - reflection density Vs print exposure - can be had at:

http://www.nolindan.com/da/support/ilmgivrcbspeed.jpg

And "paper exposure" = "time in stops" + "light intensity in stops"

The light intensity is as measured by the Darkroom Automation EM1003 enlarging meter.

http://www.nolindan.com/da/em/em1003main.htm

And stops of time are:

0 stops of time = 1.0 seconds
1 stops of time = 2.0
2 stops of time = 4.0
3 stops of time = 8.0 seconds
etc.

This is the system used in the Darkroom Automation F-Stop timer.
http://www.nolindan.com/da/fstop/fs1002main.htm

An f-stop dial for GraLab timers is provided at
http://www.nolindan.com/da/support/grastops.jpg

A table of decimal f-Stops and times is provided at
http://www.nolindan.com/da/support/stopstable.pdf

Photo Engineer · Nov 22, 2006

I refer you all again to the article by Dickerson and Zawadski on this subject in Photo Techniques about 1 year ago. They give similar curves for several papers.

The ones you show are not particularly good for Ilfords product for some reason. To see why, you should read the D&Z article. I shouldn't post the information due to copyright.

PE

Nicholas Lindan · Nov 22, 2006

Photo Engineer said:
The ones you show are not particularly good for Ilfords product for some reason.

I would like you to elaborate...

Photo Engineer · Nov 22, 2006

There should be no bumps in the curves at all. They should all have straight line mid portions with no irregularities. See the D&Z article for full sets of curves.

PE

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