favor to measure density of my stouffer stepwedge

[lhalcong]

I purchased a transmission 21 step wedge from Stouffer. I made the mistake of not buying the calibrated one. Since I am unable to spend $200 to $300 for a densitometer (even a used one on eBay runs on that range) I decided to try some of the suggestions I have read in previous threads about using my scanner and vuescan software to scan film and measure density. I understand this could be less than 100% accurate but I can live with this, all I have. I wonder if anybody with a densitometer could be so kind to measure my stepwedge for me. I will pre-pay for the shipping forth and back to me. I am in South Florida USA. not sure where else I could go or how much I would need to pay for this service.

Here is what I am trying to do: I am trying to learn and determine my expansion and contraction times in developing. I am using Ansel Adams procedure in the negative book. I shoot exclusively 35mm format so all the other processeses of taping it to the film holder kind of don't apply for me... I dont have anything else other than 35mm. So my plans now unless I find a better way, is to scan the film to determine density (zones) with my Epson Scanner. The pre-calibrated measured stepwedge is only to have as a reference to compare to the film. Although when I pre-scaned this using vuescan and my epson scanner, anything below step 8-9 seeems absolute black with same aparent density in the 2.0+/- range. Doesn't seem right to me. (Vuescan had all features turned off).

Thanks in advance for the guidance and to whomever offers to measure my stepwedge.

 

[Ken Nadvornick]

Not so sure your procedure is going to take you where you ultimately want to go, but I can calibrate your step wedge for you anyway using an essentially new Heiland densitometer.

I am the original owner, it's been lightly used, well kept, and it still matches the factory calibration strip I received with it. It also closely matches my own calibrated Stouffer wedge.

If no one geographically closer to you also offers, then PM me. Note that I'm located at the other corner in the greater Seattle, Washington area.

No charge, of course. This is supposed to be a community...



Ken

 

[kintatsu]

In Miami you should be able to find a couple shops that will measure the density for a small charge. You might even find something of interest, perhaps some film or accessories for your photography. It shouldn't be too difficult.

You can also try shooting each step individually and metering the negative with a spot meter, each 1/3 stop is about .1 step in density. You'll need FB+F, for reference. As long as your light remains constant throughout measuring, you can get reasonably accurate.

 

[Ken Nadvornick]

PM received, response sent.

Ken

 

[Nicholas Lindan]

Do you have the 35mm size or the 4x5. If it is the 35mm then you won't be able to measure the density on any ordinary densitometer.

The Stoufer wedges are within a few 0.01 OD of their 'correct' value - more accurate than the repeatability of film exposure and processing. A 21 step tablet has the steps 0.15OD / 1/2 stop apart.

 

[Ken Nadvornick]

This Heiland is the TRD 2/02 model with the interchangeable apertures down to 0.5mm, so it should be fine.

Agreed regarding the base accuracy of the Stouffer wedges. My calibrated 31-step is within +/- 0.02 over the first ten steps, and within +/- 0.07 over the final ten steps. Given that many of my shutters alone are off by 1/3 to 2/3 of a stop or more, in my real world usage those wedge numbers are not, in most cases, a significant contributor to the overall spread.

Nevertheless, just to help make this a nicer place to visit I'm still willing to help out with the OP's request.



Ken

 

[hadeer]

Into my opinion there is no need to measure your stepwedges' density because to my experience the difference with the densities printed on the stepwedge will be very small and won't have a significant effect on test results. Moreover, I a standard consumer scanner can't give you information that is precise enough, even if it's calibrated.