Stouffer 21 step tablet Question

[Gray Mitchell]

hey everyone,
just got a stouffer 21 step in the mail (uncalibrated). I am trying to calibrate my X-rie 810. does anyone know the densities that the step tablet should read...any suggestions. I know i could take the Step tablet to a lab and have it read but i was just looking for a shortcut. thanks.

[Craig Schroeder]

They go up in 0.15 (½ ƒ stop) increments. The most clear is supposed to be 0.05, so it would go 0.05, 0.20, 0.35,....on up to 3.05.

[Todd Schoenbaum]

I just looked at mine and its pretty close to what Craig said. You probably should have ordered one of their calibrated stepwedges. This is what I have and they record each step density by hand on the envelope. My values are all within .02 of what they should be, but it sure is nice to know exactly what they are.

[John Berry ( Roadkill )]

I hate to tell you this bro, but order yourself a calibrated transmission and reflection Stoffers'. Unless you want to pay someone to read it and mark it for you. That might be cheaper than a new one. I bought an X-rite 310 because I don't want to know that they are in the ballpark, I want to know what base they are on. Without a calibrated step you are only in the ballpark. A densitometer is only as good as it's calibration. Don't shortchange yourself at the last step of the game. I know how bad you want to hear " It will be close enough" but you won't hear it from me. My Step 1 on the transmission step tablet is .04. If they vary by.02 that isn't much up higher but it is quite a bit when you are trying to find the FB+f edge. Sorry, John

[Nature Photo]

Noncalibrated, values are:
0.06-0.22-0.38-0.55-0.71-0.86-1.02-1.22-1.38-1.54-1.74-1.9-2.02-2.2-2.34-2.48-2.7-2.78-2.9-3.1-3.4

So the differences (steps) come out to be:
n/a-0.16-0.16-0.17-0.16-0.15-0.16-0.20-0.16-0.16-0.20-0.16-0.12-0.18-0.14-0.14-0.22-0.08-0.12-0.20-0.30

Method: Epson 4870 and Vuescan densitometry.

[Morten]

New insterted question..
How are the experience with the Vuescan densitometry ? The report from Nature Photo Looks for me to be fairly good... Anyone with a Canon 9900F (other than me) using the Vuescan densitometry ?

Best regards
Morten :-)

[John Berry ( Roadkill )]

21 step sensitivity guide PN T2115c
.04, .20, .34, .49, .63, .79, .93, 1.07, 1.21, 1.36, 1.50, 1.66, 1.81, 1.97, 2.13, 2.27, 2.41, 2.56, 2.70, 2.86, 3.00
Method: read from calibration on envelope.
The calibrated and noncalibrated come off the same line. The calibrated ones are individually read and marked on the envelope. I would question the accuracy of scanned readings unless, at least an IT-8 has been scanned with color management software applied.

[Ed Richards]

Any one know the values for grey scale at the bottom of an IT-8 transmission target? What is Vuescan densitometry? I use Vuescan, but that is new to me.

[Doug Herta]

A calibrated density somewhere in the mix would be helpful. Densitometers should be regularly calibrated to a known density. The x-rite 361T densitometer I use is calibrated to the x-rite calibration step tablet. This means that there is at least one data point to insure internal consistancy between density and values on the step tablet. If the values are close to the expected densities AND consistant over time you are probably in good shape.

Yesterday I was measuring the 21 step Stouffer tablet with my 361T X-rite densitometer to see how the UV and ortho channels differed. The ortho channel was pretty straightforward with 0.05 changing 0.15 (+/- 0.02) fromone step to the next. UV densities are still a head scratcher for me...

[D. Poinsett]

It's probably OK to use the nominal values starting with 0.05 for clear and adding 0.15 for every step after that. I have seen over a dozen of the uncalibrated Stouffer tablets checked on a calibrated densitometer and each step was within 0.02D.

[Nature Photo]

Ed:
In Vuescan preview, press Ctrl and move the cursor over the image. The status bar will display densities on the right side.