Hi Gregory, Thank you so much for your detailed video. I recently got a densitometer and TP 4x5 (21 step) step wedge as a reference. I have a question that maybe you can answer. I know my densitometer is for B/W film but I measured an unexposed border of Velvia 50 film and I was surprised it has 2.7D as DMax. Based on the Velvia 50 datasheet it should be around 3.5-4D from my understanding. I am pretty sure I measured correctly. I use The Darkroom for E6 development and Velvia 50 should be a fresh stock. Do you have any ideas why I have this discrepancy?
I'd love to see a video about using the densitometer with C-41 negs. I have tried to do some C41 at home and I can get pretty good results now but I'd love to know how I can evaluate the negatives properly with a densitometer.
@@TheNakedPhotographer Thanks so will that be able to measure the clear part of the leader and see if the colour is where it should be or is that not what this is used for?
GREAT video again (and again). Could you add the different brands you mentioned in the description, I could not get that properly (besides xrite and kodak which are easy) Thanks, R.
@@TheNakedPhotographer yeah I'm gonna buy some, but I mean litterally what do I have to do? what kind must I get and what numbers am I gonna be looking for to be shown on the screen?
Look up Kodak Z-131 process manual online. It should be a pdf. There is a section for process control and a sheet to keep track of your readings and whether they are within aim or not.
I got a couple X-Rite 331 from a business liquidation, and not exactly sure what the numbers mean. It seems to go from about 0 to 6. I tried measuing the tint on my car windows with them, and got numbers less than 1 doing that. Is that a percentage?
No, it’s a logarithmic scale where every 0.3 is a full stop of light, that means it’s half the amount of light. So 0.0, 0.3, 0.6, 0.9, etc, each being twice as dense as the previous, or cutting the light in half from the previous number.
@@TheNakedPhotographer So if I got a reading of 0.5 on my wndow tint its letting something like 33% of light pass through? The tint doesn't seem that dark, and it would have been illegal in the state I bought the car from.
There’s no way to know if the Xrite is properly calibrated or if it would give an accurate reading on a tinted window versus the film it was designed for.
@@TheNakedPhotographer I did have a sheet similar to this, and the readings were a few hundredths off on the samples. www.xrite.com/-/media/global-product-images/c/calibration-reference-for-model-361t/361-68.png
Some people like to graph the density values in relation to exposure to see the contrast, speed, and shadow/highlight separation as a line called the H&D curve. It can be a useful tool for comparing films or developers.
The shadow density (semi-clear area) is primarily effected by exposure. So long as development is in the ballpark, only changes in exposure will effect changes in this value. In order for the near darkest shadows to print out as such, they have to have a certain density, where marginally more density will yield a lighter shadow and a lesser density (and all lower values) will yield only a maximum black your print paper can produce. Testing of paper can refine that target value, but 0.1 - 0.2 density (above the natural density of the film and emulsion itself) is usually the value you seek. You increase or decrease this value by changing the ISO of the film using a "standard" development process. Once you have a film speed (ISO) which hits your target density for your combination of camera, film and development method, you look at the highest value (darkest negative value) which allows that negative to yield a print which has near-whites, just on the edge of the whitest tone the paper can produce. On film, that value is adjusted by development (time, temperature, type pf developer). the trick is that a slight change in development will not upset your film speed standard, so you shoot film at your standard ISO, then develop it so that the density range of the film negative is close to a perfect match for the requirements of your printing paper. The procedure to do all of this requires a certain amount of trial and error, plus an absolutely rigid control over processing variables. That why most folks will shoot film at box speed and develop in D-76 at recommended time. However, the payback for this effort is a negative which is so easy to print, and an understanding of what your film and development can do if you want to stray to get some special effect. (Note that you can eyeball the lightest print tone values, or you can use a "reflection" densitometer to measure those values on your test print. A transmission densitometer won't do this.)
I've used mine to calibrate my enlarger meter (RH Analyzer Pro) as matching numbers is a lot easier than attempting to eyeball gray against a reference card. I've also used mine to inspect C-41 Process Control Strips as a way to periodically check that my process and chemistry is producing usable results without having to risk film that I care about.
@@randallstewart175 I read all that, very interesting. Can I bounce my understanding of this off you? So for zone 1/2 densities on the negative, if they are too faint (i.e not registering at all on the print) then it's more efficient to remedy this by reducing your EI rather than by increasing development. You could increase development but then you run the risk of your zone 8/9 whites blowing out on the print. But that last point doesn't really matter that much with variable contrast paper (or does it?). In summary, the main thing is to get your EI / dev time matched so that zone 1/2 detail is just appearing on the negative and therefore separable from pure black on the print. You may be pushing or pulling the film without realizing it (although we are assuming here that your EI is not a million miles from box speed!), but for that EI/dev time you are at least using the film optimally. If you were writing a "developer primer for dummies" would you endorse all that? Cheers, Keith.
@@emotown1 I'm not sure I followed your points accurately, so let's summarize. The exposure largely controls the threshold where the shadow (light) values will first appear on the film as very faint imaging. So if you are not getting printable density from your zone 2 exposure, you need to lower you film "speed" by increasing the exposure for that value. Development changes have almost no measurable impact on the film density of the zone 1/2 values. So, if you are trying to "zone" adjust a given film/developer combination, you start with a middle of the road developing time/temp, shoot the same subject target over a range of EI, develop and select an EI (speed) which yield the best EI. Then, you shoot some of the same target at that EI and develop at various time/temp until you get highlights which match your goals for your printing paper. Thus the old saw: Expose for the shadows and develop for the highlights. If you over develop your film and blow out the highlights, then they are gone, and no variable contrast paper will recapture them for you. My personal practice is to use a standard time and temp to process my B&W film to insure a full shadow detail capture and variable contrast paper to adjust overall contrast range in the print. This will manage most low contrast subjects. If I determine that my subject has exceptionally high contrast, I might reduce development time (pull the process) to avoid "blowing out" the highlights, but I rarely run into the problem.
Hi Gregory,
Thank you so much for your detailed video. I recently got a densitometer and TP 4x5 (21 step) step wedge as a reference.
I have a question that maybe you can answer. I know my densitometer is for B/W film but I measured an unexposed border of Velvia 50 film and I was surprised it has 2.7D as DMax. Based on the Velvia 50 datasheet it should be around 3.5-4D from my understanding. I am pretty sure I measured correctly. I use The Darkroom for E6 development and Velvia 50 should be a fresh stock. Do you have any ideas why I have this discrepancy?
I'd love to see a video about using the densitometer with C-41 negs. I have tried to do some C41 at home and I can get pretty good results now but I'd love to know how I can evaluate the negatives properly with a densitometer.
For color, the densitometer is better used for reading step wedges to make H&D curves and to plot your aim values from a process control strip.
@@TheNakedPhotographer Thanks so will that be able to measure the clear part of the leader and see if the colour is where it should be or is that not what this is used for?
So when gathering both transmission and reflective densitometry figures, how do you use or compare both?
GREAT video again (and again). Could you add the different brands you mentioned in the description, I could not get that properly (besides xrite and kodak which are easy) Thanks, R.
Done
Super video!
I always avoided densitometry, but it seems a lot less scary than I thought. Thanks!
i just got one of these lol
thank you for the video!
How would I use this for checking the quality of my c41 film developer + c41 process?
You need to run process control strips for that
@@TheNakedPhotographer yeah I'm gonna buy some, but I mean litterally what do I have to do? what kind must I get and what numbers am I gonna be looking for to be shown on the screen?
Look up Kodak Z-131 process manual online. It should be a pdf. There is a section for process control and a sheet to keep track of your readings and whether they are within aim or not.
@@TheNakedPhotographer thank you
is the x right 410 ok?
I got a couple X-Rite 331 from a business liquidation, and not exactly sure what the numbers mean. It seems to go from about 0 to 6. I tried measuing the tint on my car windows with them, and got numbers less than 1 doing that. Is that a percentage?
No, it’s a logarithmic scale where every 0.3 is a full stop of light, that means it’s half the amount of light. So 0.0, 0.3, 0.6, 0.9, etc, each being twice as dense as the previous, or cutting the light in half from the previous number.
@@TheNakedPhotographer So if I got a reading of 0.5 on my wndow tint its letting something like 33% of light pass through? The tint doesn't seem that dark, and it would have been illegal in the state I bought the car from.
There’s no way to know if the Xrite is properly calibrated or if it would give an accurate reading on a tinted window versus the film it was designed for.
@@TheNakedPhotographer I did have a sheet similar to this, and the readings were a few hundredths off on the samples. www.xrite.com/-/media/global-product-images/c/calibration-reference-for-model-361t/361-68.png
Does the 810 do colour positive (e6) control strips?
The 811 does, but not the 810. I think there was a conversion available to upgrade the 810 to the 811.
Does anything of this process drastically change when trying to measure color negative/positive films?
With color you have three curves instead of one: red, blue, and green. Positive films are plotted with the shoulder on the left and toe on the right.
great stuff! do you think you'll do a video on two bath developers?
Someday perhaps
I'm sorry but why would I get one ie what would I do with those values
Some people like to graph the density values in relation to exposure to see the contrast, speed, and shadow/highlight separation as a line called the H&D curve. It can be a useful tool for comparing films or developers.
The shadow density (semi-clear area) is primarily effected by exposure. So long as development is in the ballpark, only changes in exposure will effect changes in this value. In order for the near darkest shadows to print out as such, they have to have a certain density, where marginally more density will yield a lighter shadow and a lesser density (and all lower values) will yield only a maximum black your print paper can produce. Testing of paper can refine that target value, but 0.1 - 0.2 density (above the natural density of the film and emulsion itself) is usually the value you seek. You increase or decrease this value by changing the ISO of the film using a "standard" development process. Once you have a film speed (ISO) which hits your target density for your combination of camera, film and development method, you look at the highest value (darkest negative value) which allows that negative to yield a print which has near-whites, just on the edge of the whitest tone the paper can produce. On film, that value is adjusted by development (time, temperature, type pf developer). the trick is that a slight change in development will not upset your film speed standard, so you shoot film at your standard ISO, then develop it so that the density range of the film negative is close to a perfect match for the requirements of your printing paper. The procedure to do all of this requires a certain amount of trial and error, plus an absolutely rigid control over processing variables. That why most folks will shoot film at box speed and develop in D-76 at recommended time. However, the payback for this effort is a negative which is so easy to print, and an understanding of what your film and development can do if you want to stray to get some special effect. (Note that you can eyeball the lightest print tone values, or you can use a "reflection" densitometer to measure those values on your test print. A transmission densitometer won't do this.)
I've used mine to calibrate my enlarger meter (RH Analyzer Pro) as matching numbers is a lot easier than attempting to eyeball gray against a reference card.
I've also used mine to inspect C-41 Process Control Strips as a way to periodically check that my process and chemistry is producing usable results without having to risk film that I care about.
@@randallstewart175 I read all that, very interesting. Can I bounce my understanding of this off you? So for zone 1/2 densities on the negative, if they are too faint (i.e not registering at all on the print) then it's more efficient to remedy this by reducing your EI rather than by increasing development. You could increase development but then you run the risk of your zone 8/9 whites blowing out on the print. But that last point doesn't really matter that much with variable contrast paper (or does it?).
In summary, the main thing is to get your EI / dev time matched so that zone 1/2 detail is just appearing on the negative and therefore separable from pure black on the print. You may be pushing or pulling the film without realizing it (although we are assuming here that your EI is not a million miles from box speed!), but for that EI/dev time you are at least using the film optimally.
If you were writing a "developer primer for dummies" would you endorse all that? Cheers, Keith.
@@emotown1 I'm not sure I followed your points accurately, so let's summarize. The exposure largely controls the threshold where the shadow (light) values will first appear on the film as very faint imaging. So if you are not getting printable density from your zone 2 exposure, you need to lower you film "speed" by increasing the exposure for that value. Development changes have almost no measurable impact on the film density of the zone 1/2 values. So, if you are trying to "zone" adjust a given film/developer combination, you start with a middle of the road developing time/temp, shoot the same subject target over a range of EI, develop and select an EI (speed) which yield the best EI. Then, you shoot some of the same target at that EI and develop at various time/temp until you get highlights which match your goals for your printing paper. Thus the old saw: Expose for the shadows and develop for the highlights. If you over develop your film and blow out the highlights, then they are gone, and no variable contrast paper will recapture them for you. My personal practice is to use a standard time and temp to process my B&W film to insure a full shadow detail capture and variable contrast paper to adjust overall contrast range in the print. This will manage most low contrast subjects. If I determine that my subject has exceptionally high contrast, I might reduce development time (pull the process) to avoid "blowing out" the highlights, but I rarely run into the problem.