How essential is a densitometer?

[mark]

Wanting to do negs for Carbon printing. Sandy's book uses a lot of desitometer readings as does his online stuff. I don't know what any of it means. How essential is a densitomiter in this process?

 

[jim10219]

Not at all. I had two. Bought one and was given another. Sold them both.

There are things you can use them for, for sure. But for my purposes, I preferred to just scan the prints into the computer and use the eyedropper in photoshop to get my readings. It may not provide an absolute reading for comparing with results in books, but it tells me what I need to know and how changes to my process effect changes in my product. And, best of all, since I save these files while scanning them, I can keep a log of what produced what results and easily go back and compare, should I need to.

 

[Vaughn]

I believe that one can do without -- people scan in their tests and read them somewhat like a densitometer in PhotoShop. Don't asks me how! LOL!

 

[Andrew O'Neill]

You don't really need one. Are you using in-camera negatives? I never bothered with densitometry even with digital negatives.

 

[RalphLambrecht]

Wanting to do negs for Carbon printing. Sandy's book uses a lot of desitometer readings as does his online stuff. I don't know what any of it means. How essential is a densitomiter in this process?

a densitometer is as essential to photographic processing as a lightmeter is to exposure.

 

[ced]

I think they are difficult to find cheap so a reasonable alternative could be a "Stouffer Step Wedge".
https://www.stouffer.net/TransPage.htm

 

[Bob Carnie]

If you are trying to linearize a process , a densitometer is essential, the problem is on understanding how it all relates. My process to make digital negatives were calibrated within a quadtone rip program that Ron Reeder personally did for me , I still today use
his curve that I require to make negs on an inkjet printer... For my Durst Lambda process for making silver paper , silver film and before Cibachrome and RA 4 , I use an X Rite densitometer that is built into the software program and with magic the Lasers are calibrated to make a linearized 21 step wedge. Once this step wedge is done then its good to go.
So these two examples are the only time I require a densitometer, If I did not work this way but was only processing my film and printing on enlargers I see absolutely no need for them for 90% of photographic work.

 

[hadeer]

Wanting to do negs for Carbon printing. Sandy's book uses a lot of desitometer readings as does his online stuff. I don't know what any of it means. How essential is a densitomiter in this process?

Hi
It makes sense to print a stepchart on the transparency when you switch to a different one, and then check with a densitometer if the densities differ with the older material. That saves you unwanted surprises when printing new stuff.

 

[mark]

You don't really need one. Are you using in-camera negatives? I never bothered with densitometry even with digital negatives.

I'll be using both in camera and digital negatives.

 

[Bob Carnie]

For digital negatives.. one is using an inkjet negative which requires laying density of ink precisely to values seen in the original file.

There are many software programs.. Reeder Harrington Quadtone Rip, Mark Nelson system, Richard Boutwells system... all are designed to calibrate a curve that allows L values to be
place where they are suppose to be to look like a normal negative... This is done within their programs and there are many options on how to measure the final values.

It must be stated that the inkjet printer has no idea where to place values of ink to correspond to density required to make a good black and white negative. by printing a100 step wedge on film, then printing at a known good balance . then having the software analyze each step and creating a density shift to make a L 75 value on the file print out as a L 75 on the print.... this is where these software /densitometers come in their form.... once a curve has been created and the ink responds to its new position then you are good to go.. Once a good curve that makes a good negative is achieved I have found that you can adjust the process to match your needs., Whether it is adjusting the contrast balance of the image on screen or adjusting your process balance it becomes pretty easy.

 

[Andrew O'Neill]

For digital negatives.. one is using an inkjet negative which requires laying density of ink precisely to values seen in the original file.

There are many software programs.. Reeder Harrington Quadtone Rip, Mark Nelson system, Richard Boutwells system... all are designed to calibrate a curve that allows L values to be
place where they are suppose to be to look like a normal negative... This is done within their programs and there are many options on how to measure the final values.

It must be stated that the inkjet printer has no idea where to place values of ink to correspond to density required to make a good black and white negative. by printing a100 step wedge on film, then printing at a known good balance . then having the software analyze each step and creating a density shift to make a L 75 value on the file print out as a L 75 on the print.... this is where these software /densitometers come in their form.... once a curve has been created and the ink responds to its new position then you are good to go.. Once a good curve that makes a good negative is achieved I have found that you can adjust the process to match your needs., Whether it is adjusting the contrast balance of the image on screen or adjusting your process balance it becomes pretty easy.

I use Chartthrob to generate curves in PS, and QTR to control how much ink for each colour is laid down. The only time I use a densitometre is when generating in-camera film curves...which really makes getting from A to Zed quick and easy. With an operation such as yours, Bob, I can certainly appreciate and understand the amount of control required, for consistent results. Congrats on the major move to your new space! Looks like it was a hell of a job! You'll need a mini-vacation now! Cheers!

 

[RalphLambrecht]

I think they are difficult to find cheap so a reasonable alternative could be a "Stouffer Step Wedge".
https://www.stouffer.net/TransPage.htm

That works well within its limits.

 

[DREW WILEY]

Numerous people made magnificent carbon prints long before densitometers were ever invented. So explain that. But I personally use a densitometer quite a bit when it is important to critically understand what's going on. Step wedge are used in conjunction with densitometers for plotting purposes, not as an alternative to them. But you can use a basic Stouffer step wedge as a visual reference for approximate film densities if you buy a calibrated one.

 

[Bob Carnie]

If you are using in camera negs, and have your exposure development process nailed their is no need for densitometers. but if you are using inkjet negs you absolutely need to read the densities of the output then create a curve that will drive the info to the input values, no getting around this. Once it is done once it is good to go for years btw, just a little technical snag most of us are not good at.

 

[nmp]

For digital negatives, QTR based methods seem to use densities or L*ab's for which a densitometer or a spectrophotometer would be essential. However if you are using any of the other methods like ChartThrob, as pointed out earlier, you can made do with a scanner to create Photoshop correction curves. I wanted to buy a densitometer just to check my process against known literature in terms of Dmax, Dmin etc. However, it seems I can calculate those from the L*ab values I get from my Colormunki spectrophotometer. So no densitometer needed for me.

 

[jim10219]

To further expand on my process for inkjet negatives with alternative process printing, I first create a digital negative with 11 small boxes stacked in a row, ranging from 0-100% coverage at 10% intervals. I then repeat these boxes for as many time as will fit on the negative. I then coat whichever paper and with whichever emulsion I plan to test, and put a sheet of dense cardstock over all but one of the rows of boxes. Then, I move the paper back to expose a new row at regular intervals. So I wind up with a row of the same negative, each with, let's say 3 seconds more of exposure than the previous row. I then use this chart to determine the proper amount of time needed to get the densest dark areas without compromising my brightest highlights. All this does is figure out my exposure time.

I then make a new digital negative, this time with 100 boxes (in a 10x10 grid), ranging from 1-100% at 1% intervals (the area around the boxes can be used for my 0%). I then print that using the same paper and chemistry as before. I make sure that the information on this negative will be small enough to fit on my scanner's glass plate. Then, after development and letting it dry, I scan it into the computer. From here, I use the eyedropper tool in PS to take a sample of each square so I can work out a calibration curve. It's important to set the eye dropper to sample a large enough area so that you're getting an accurate reading. Also, be aware of any areas that didn't coat evenly, as you may get different densities due to coating inconsistencies.

Anyway, the second chart gives me the output as defined by the input. So I can go through the chart and find the output I'm looking for, and know which input (the amount of ink laid down by the inkjet printer) that will be required to achieve that output. So say for instance, that 20% density on my inkjet will get me 35% density on my alt. process print. In the curves tool, I can select an input of 35 to an output of 20. I will then build the entire curve with this information and smooth it out as necessary, as invariably some inconsistencies in my coating and developing process will come up. However, you should be able to spot the trends and average something out to get the accuracy you need. Lastly, if you choose, you can recreate the 10x10 grid and apply the curve to it to check you results.

I find this method much easier than using a densitometer, since I can build the curve while taking measurements in Photoshop. There are some details I left out that are more applicable to my own equipment. You'll have to figure out the quirks of your own equipment and figure out the best way to utilize it yourself. For instance, I have to choose specific printer and scanner properties and color profiles to ensure maximum density range, and make sure that the method I used to create the grids properly translates to editing the negatives. Otherwise you'll just be creating curves that allow you to print the best charts and don't really have an effect on negatives. There is a lot of trial and error involved here, but once you get the process down, it's not too hard or confusing to do it again. So if you change the paper, the sizing, the emulsion formula, the pigment, the UV exposure light, the transparency film, or the inkjet printer, you can easily recalibrate your curve to accommodate it.