I thought all Ilford papers were the same speed...?

[tezzasmall]

I don't know why I thought this, but I thought all Ilford papers were the same speed...?

I was doing some test prints for the Postcard Exchange Round this week, but was running low of the actual Ilford Postcard RC paper. So... I did some tests on Ilford MG RC paper and then put some postcard paper in the easel to print the final prints. Wow!!! The end results were no where near the same, with the two being totally different in exposure.

I now presume that one can't test strip on one type of paper and then just use another type with the same exposure?

Did all papers used to be the same speed, regardless of name and surface, as long as they were all Ilford or have I just dreamt all of this?

Comments and thoughts?

Terry S

 

[John Salim]

Hi Terry,
They're suppose to be the same speed, but unless they're the same production batch they can be different.

I usually notice when starting a new box ( same size - different batch of Multigrade IV ) I find the speed is very slightly different ( processing through a very stable machine processor ).

John S

 

[faberryman]

Multigrade Cool Tone, Classic, and Warm Tone are all different speeds. Test strips need to be from same paper, preferably same box.

 

[Sirius Glass]

I never thought that all papers were the same speed. How hard would that be to accomplish? More importantly why would companies do that? Besides for some printing situations [example a dense negative] I would want a fast paper and some [very thin, low density negative] a slow paper.

 

[MattKing]

I wouldn't be surprised if some of the roll papers are speed matched.
And if the OP switched from the Postcard Portfolio paper to another size of the Portfolio paper it would surprise me if there was a large difference in speed.
But I wouldn't have expected the Portfolio paper to be the same speed as the regular weight MGIV RC paper, unless by coincidence it was designed that way.

 

[tezzasmall]

Thanks for all of the replies so far.

I can see that two totally different boxes in age might 'mature' to different speeds, but I was quite surprised when two different types of Ilford papers bought at the same time now seemed to be so different in the exposure required. For information, the postcard paper was MUCH quicker than RC gloss paper.

I just had it in my head for some reason that there was base emulsion, made each time at a certain speed across the range, (like film) and then the papers would be completed with a eg another surface emulsion for the various finishes ie gloss, pearl, lustre etc. But obviously not.

As mentioned, I must look at all of the fact sheets for the different papers on the Ilford site and see what speeds are quoted.

I never thought that all papers were the same speed. How hard would that be to accomplish? More importantly why would companies do that? Besides for some printing situations [example a dense negative] I would want a fast paper and some [very thin, low density negative] a slow paper.

I think you have slightly confused the question there. I can understand your bit about fast and slow papers for dense and thin negatives but that's not quite what I meant.

Terry S

 

[MattKing]

I just had it in my head for some reason that there was base emulsion, made each time at a certain speed across the range, (like film) and then the papers would be completed with a eg another surface emulsion for the various finishes ie gloss, pearl, lustre etc. But obviously not.

The surface gloss isn't determined by the emulsion. It is determined by the substrate that the emulsion is applied to.
Out of curiosity, was the RC Portfolio Postcard paper glossy, pearl or ?
And was the "regular" RC paper on Portfolio stock or regular, and was it normal, warmtone, or cooltone?

 

[locutus]

Double check the little folded pamphlet that comes with your paper packet, it will list speeds. Paper ISO speeds work the same as film ISO speeds (so ISO(p) 200 is twice as fast as ISO(p) 100).

The pamphlet has a table with speeds of current emulsions.

Although this is a bit of a limited comparison due to finishes etc...

 

[removed account4]

i once called and asked kodak about paper speeds
and they told me the rated iso of paper has nothing to do with film iso. --- its a different scale.
years ago i spent a few days rating paper i had on hand.
some was graded some vc, some silver chloride, some bromochloride,
some i don't know what, some fiber some rc
most of the papers were between 6 or so and a small fraction below 1.

PE and others have shown results or reported them showing ilford mg rc having an iso relative to film as being about 24...
i am sure if you are an emulsion scientist or maker with experience you can make an emulsion that is faster
but unless you are exposing in a camera imnot sure what the point would be to have a extremely high speed paper emulsion...
darkroom enlargers don't usually operate at times less than 1/10thS...

have fun !

 

[dwross]

I don't know why I thought this, but I thought all Ilford papers were the same speed...?

I was doing some test prints for the Postcard Exchange Round this week, but was running low of the actual Ilford Postcard RC paper. So... I did some tests on Ilford MG RC paper and then put some postcard paper in the easel to print the final prints. Wow!!! The end results were no where near the same, with the two being totally different in exposure.

I now presume that one can't test strip on one type of paper and then just use another type with the same exposure?

Did all papers used to be the same speed, regardless of name and surface, as long as they were all Ilford or have I just dreamt all of this?

Comments and thoughts?

Terry S

You're partly correct (at least in a historical sense). Back in the days before VC paper, manufacturers tried to match the speeds of the different grades of paper within the same name, for example, grades 1-5 of Kodabromide. That way, if you figured out the correct exposure using one grade of Kodabromide, but decided that the print was too flat or too contrasty, you could switch grades up or down and not have to redetermine the correct exposure. I don't know if it worked perfectly all the time, but gotta say it was an excellent goal.

 

[Arklatexian]

I don't know why I thought this, but I thought all Ilford papers were the same speed...?

I was doing some test prints for the Postcard Exchange Round this week, but was running low of the actual Ilford Postcard RC paper. So... I did some tests on Ilford MG RC paper and then put some postcard paper in the easel to print the final prints. Wow!!! The end results were no where near the same, with the two being totally different in exposure.

I now presume that one can't test strip on one type of paper and then just use another type with the same exposure?

Did all papers used to be the same speed, regardless of name and surface, as long as they were all Ilford or have I just dreamt all of this?

Comments and thoughts?

Terry S

You did not dream all of that, you just assumed it to be true based on something that was incorrect. In the US, each manufacturer made some (very few) papers that were the same speed. Most, however, varied in speed. This was true of Kodak, Ansco, probably DuPont, etc. Example: Kodak Kodabromide Single Weight Glossy had a different speed than did Medalist Single Weight Glossy. (Now watch someone prove me wrong about these two papers. It has only been at least 40 years or more since I have printed on either)................Regards!

 

[Photo Engineer]

VC papers are intrinsically different in speed from graded papers. One has two emulsions sensitive to G and B light and the other usually has one layer (or emulsion) sensitive to just B light. That, in addition to batch variations compounds this type of problem.

Papers are made two ways, matching speed at a "swing point" which is about midscale or about 0.8 to 1.0 density or just letting papers fall where manufacturing makes them. This also confounds the problem. Kodak used the "swing point" method so that when one got a good mid scale print, one could change papers or contrast grades with little or no problem.

PE

 

[tezzasmall]

Out of curiosity, was the RC Portfolio Postcard paper glossy, pearl or ?
And was the "regular" RC paper on Portfolio stock or regular, and was it normal, warmtone, or cooltone?

Matt,

The RC Postcard paper was Pearl surface and the 'regular' RC paper on 'regular' paper stock used (which is much thinner than the former) was glossy, normal.

Thanks to everyone else for your comments.

I'm now off to the Ilford site to read over the data sheets, which will hopefully put my mind at rest one way or the other.

Terry S