Delta X Criterion

[tom williams]

Can anyone attribute this article, for which I post an image of the first of 13 pages?

 

[Stephen Benskin]

Can anyone attribute this article, for which I post an image of the first of 13 pages?

View attachment 308694

I wrote it. It's based on the paper Nelson, C.N. and Simonds, J.L, Simple Methods for Approximating the Fractional Gradient Speeds of Photographic Materials, JOSA, vol. 46, n. 5, May 1956.

 

[tom williams]

Stephen, thanks. I appreciated the paper, and thought I might find some related writings by discovering the author. Do such exist, on related topics? My interest is somewhat general - trying to understand the basics.

I hope that it wasn't improper for me to display an image of the first page.

cheers
Tom

 

[Stephen Benskin]

Stephen, thanks. I appreciated the paper, and thought I might find some related writings by discovering the author. Do such exist, on related topics? My interest is somewhat general - trying to understand the basics.

I hope that it wasn't improper for me to display an image of the first page.

cheers
Tom

Tom,

It depends what you mean by basics.

C.N. Nelson, Safety Factors in Camera Exposures, Photographic Science and Engineering, Vol 4, Number 1, Jan-Feb 1960, contains the argument for the 1960 black and white film speed change that utilizes Delta-X (and still does).

D. Connelly, Calibration Levels of Films and Exposure Devices, The Journal of Photographic Science, Vol 16, 1968, breaks down the relationship between the meter and film exposure.

Stimpson, Allen, An Interpretation of Current Exposure Meter Technology, Photographic Science and Engineering, Vol 6, Number 1, Jan-Feb 1962, is more about meters and photo cells, and proposed changes to the exposure meter standard.

Scudder, James F., Nelson, C.N., Stimson, Allen, Re-evaluation of Factors Affecting Manual or Automatic Control of Camera Exposure, Journal of the SMPTE, Vol 77, Jan 1968. Much of the paper appears in the appendix of the next exposure meter standard.

Chapters on Sensitometry and Tone Reproduction in The Theory of the Photographic Process, 3rd Edition.

Stroebel, Leslie, Compton, John, Current, Ira, and Zakia, Richard, Photographic Materials and Processes. I wore out my original copy.

Loyd Jones' seminal work in the 1940s.

I've attached another paper of mine, What is Normal. It's on determining a developmental model. The bibliography references a few of Jones' papers.

This should be a good start.

Stephen

 

[MattKing]

Can anyone attribute this article

I wrote it.

We are a full service resource here on Photrio, aren't we?

 

[tom williams]

That paper - "What Is Normal" - is an example of a useful reference. Thank you for that and the other references.

 

[tom williams]

We are a full service resource here on Photrio, aren't we?

Without a doubt.

A related issue: after finding that Stephen Benskin wrote the paper I queried about, I seached and found threads he participated in. Those that I checked out were good - but could have been even more useful had the images (of graphs in particular) still been accessible. The thread I'm thinking about was from 2008, I believe. Is there a time limit on preservation of attachments in posts?

 

[MattKing]

Without a doubt.

A related issue: after finding that Stephen Benskin wrote the paper I queried about, I seached and found threads he participated in. Those that I checked out were good - but could have been even more useful had the images (of graphs in particular) still been accessible. The thread I'm thinking about was from 2008, I believe. Is there a time limit on preservation of attachments in posts?

No, but I'd be willing to bet that the links that were the source of the graphs are probably no longer effective.

 

[ic-racer]

The way non-ISO/ASA approximations of fractional gradient speeds simplify my workflow is that they eliminate the need to construct a family of curves for the speed test.

 

[Stephen Benskin]

The lesson I find to be most interesting with Delta-X is how the concept of film speed is actually different than the general perception of it.

 

[tom williams]

Tom,

It depends what you mean by basics.

C.N. Nelson, Safety Factors in Camera Exposures, Photographic Science and Engineering, Vol 4, Number 1, Jan-Feb 1960, contains the argument for the 1960 black and white film speed change that utilizes Delta-X (and still does).

D. Connelly, Calibration Levels of Films and Exposure Devices, The Journal of Photographic Science, Vol 16, 1968, breaks down the relationship between the meter and film exposure.

Stimpson, Allen, An Interpretation of Current Exposure Meter Technology, Photographic Science and Engineering, Vol 6, Number 1, Jan-Feb 1962, is more about meters and photo cells, and proposed changes to the exposure meter standard.

Scudder, James F., Nelson, C.N., Stimson, Allen, Re-evaluation of Factors Affecting Manual or Automatic Control of Camera Exposure, Journal of the SMPTE, Vol 77, Jan 1968. Much of the paper appears in the appendix of the next exposure meter standard.

Chapters on Sensitometry and Tone Reproduction in The Theory of the Photographic Process, 3rd Edition.

Stroebel, Leslie, Compton, John, Current, Ira, and Zakia, Richard, Photographic Materials and Processes. I wore out my original copy.

Loyd Jones' seminal work in the 1940s.

I've attached another paper of mine, What is Normal. It's on determining a developmental model. The bibliography references a few of Jones' papers.

This should be a good start.

Stephen

I found "Basic Photographic Materials and Processes" (440pp 2000 2nd edition) and "Photgraphic Processes and Materials" (585pp,1986), both by Stroebel, Compton, Current,and Zakia, at thriftbooks.com, under $5 each. Thanks for the reference, hope I can make something of it.
cheers
Tom

 

[john_s]

The lesson I find to be most interesting with Delta-X is how the concept of film speed is actually different than the general perception of it.

I found this article very interesting. Now that I've used all of my Neopan400, I have decided for various reasons to use HP5+. I have a densitometer and I haven't tested film for many years. I prefer a negative that's not very contrasty, and the "Zone 1" density at box speed I've been achieving in tests has been somewhat below 0.1. However, just before I read the article, I decided that the gradient around Zone 1 was enough to get some detail if I needed it. Some printing will reveal if that's correct, but the article led to some cause for optimism.

 

[Bill Burk]

Without a doubt.

A related issue: after finding that Stephen Benskin wrote the paper I queried about, I seached and found threads he participated in. Those that I checked out were good - but could have been even more useful had the images (of graphs in particular) still been accessible. The thread I'm thinking about was from 2008, I believe. Is there a time limit on preservation of attachments in posts?

Let us know about dead links and maybe we can find the graphs.

My site was down for a while but I found a new hosting provider. So try this link…

https://beefalobill.com/benskin/

 

[tom williams]

I'll see if I can find the relevant thread. It may actually have been an APUG archived thread. I searched here and found no Benskin posts earlier than 2009.

 

[Stephen Benskin]

Let us know about dead links and maybe we can find the graphs.

My site was down for a while but I found a new hosting provider. So try this link…

https://beefalobill.com/benskin/

FYI, The link isn't working for me Bill. This one did:

http://beefalobill.com/benskin/content