F stop printing

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nmp

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never heard of it. just make plain old test strips and hit the button x-times, who would have known this subject was this controversial
Terminology itself is rather confusing. There is no "f" involved here since you are not changing the aperture of the enlarging lens. It is simply "stop" printing where each exposure is a multiple of the preceding one, which is like doing a Stouffers but without it. It is useful if you are starting out totally in dark about where the exposure is going to fall - 1 second or a 100. Once you are in the ballpark, you can fine tune by the old fashioned way - using equal steps. You are not trying to make the characteristiuc curve, only trying to to get the optimum exposure for the negative at hand.

:Niranjan.
 

jnk

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Terminology itself is rather confusing. There is no "f" involved here since you are not changing the aperture of the enlarging lens. It is simply "stop" printing where each exposure is a multiple of the preceding one, which is like doing a Stouffers but without it. It is useful if you are starting out totally in dark about where the exposure is going to fall - 1 second or a 100. Once you are in the ballpark, you can fine tune by the old fashioned way - using equal steps. You are not trying to make the characteristiuc curve, only trying to to get the optimum exposure for the negative at hand.

:Niranjan.

I see. so it is to get close, sounds useful but I do not need more controversy in my life.
 

grain elevator

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It is simply "stop" printing where each exposure is a multiple of the preceding one, which is like doing a Stouffers but without it. It is useful if you are starting out totally in dark about where the exposure is going to fall - 1 second or a 100. Once you are in the ballpark, you can fine tune by the old fashioned way - using equal steps. You are not trying to make the characteristiuc curve, only trying to to get the optimum exposure for the negative at hand.

This is exactly how I use it. With a simple traditional timer. When I need to get a ballpark exposure, I do a 1 stop spaced test strip by simply setting an appropriate time, then exposing once for the first step, cover that and exposure the rest of the strip once more, cover that and expose the rest twice, then four times (more gets tedious, I open usually open the aperture if more is needed).
Another test strip to get closer is then done in linear intervals. I can still roughly convert these to fractions of a stop if I need to make calculations. I've found that trying to get all the way to an accurate exposure in one test strip rarely works for me, unless I work with several very similar negatives. So the two strips approach works for me and the more roughly spaced first strip sometimes saves me from doing even more strips.
 

Vaughn

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I see. so it is to get close, sounds useful but I do not need more controversy in my life.
Agreed. The subjective and the objective tend to get confused a little with controversy.
 

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For me switching to f-stop printing made things quite difficult at first, but once I got my head around it, making a print became a lot easier!
Then I built my own darkroom timer especially for this and it does all the calculations for me.
When making test strips I choose a start exposure and specify the spacing between exposures (full/half/third/quarter/... stops) and the timer does the rest for me.
It took me some time to get familiar with it but now I reach my end goal much faster than when using "regular" test strips.

Both will give you the same end result, it's just a matter of what's most convenient for you!
 

Sirius Glass

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The problem with the seconds steps is that it may have started out with either too much exposure or too little exposure and the whole sheet is wasted because it did not have enough overall exposure range. f/stop exposures cover the range exponentially with powers of two. I prefer to at least start with the f/stop exposures.
 

MattKing

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As mentioned earlier in the thread, the f-stop or stop approach does have a further fundamental advantage even after you finish the early test strip process.
Once you become familiar with it, you become quite proficient at recognizing the result of a 1/2, 1/3, 1/4 or 1/6 of a stop change in exposure. And that proficiency is independent of the base exposure time. As an example, whether your base exposure is 8 seconds or 64 seconds, an exposure increase of a 1/2 stop will appear the same - whether it is 3 extra seconds added to the 8 second exposure, or 26 seconds added to the 64 second exposure.
FWIW, the effect of a 1/3 stop change is very clear. For fine tuning, the effect of a 1/6 stop change is subtle, but sometimes quite important.
The proficiency comes when you establish a visual connection between the increments and the results. And that connection works directly with stop increments, and doesn't work directly with linear increments.
 

albada

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an exposure increase of a 1/2 stop will appear the same

That's true at a given grade (contrast). But a boost of 1/2 stop will look much different at grade 1 versus grade 5, although with enough experience (which I lack), I suppose one will develop that intuition across a range of grades.
 

albada

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For me switching to f-stop printing made things quite difficult at first, but once I got my head around it, making a print became a lot easier!
Then I built my own darkroom timer especially for this and it does all the calculations for me.
When making test strips I choose a start exposure and specify the spacing between exposures (full/half/third/quarter/... stops) and the timer does the rest for me.
It took me some time to get familiar with it but now I reach my end goal much faster than when using "regular" test strips.

Good for you! Did you use an Arduino? I've used both an Arduino and an evaluation board for the PIC18 (I built two controllers).
I programmed the test-strip feature to put the base exposure at the left, center, or right-end of the test-strip. I usually use "center". "Left" is good for determining how much to burn, and "right" is good for deciding a dodge.
One feature I really like is turning off the safelight when the enlarger is on for any reason (focusing or exposing). I used a relay, but a triac should work equally well.
To conserve space on the LCD, I use tenths of stops for everything, which works well for exposure arithmetic, but it can't represent third or quarter stops. For those, I must use steps of 0.2 or 0.3 stops instead.
 

faberryman

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The problem with the seconds steps is that it may have started out with either too much exposure or too little exposure and the whole sheet is wasted because it did not have enough overall exposure range. f/stop exposures cover the range exponentially with powers of two. I prefer to at least start with the f/stop exposures.

I typically print full frame at fixed print sizes so I have a pretty good idea what the initial exposure needs to be. Different people have different workflows so f-stop printing may have more or fewer advantages for them.
 

Sirius Glass

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I typically print full frame at fixed print sizes so I have a pretty good idea what the initial exposure needs to be. Different people have different workflows so f-stop printing may have more or fewer advantages for them.

In the past that was true for me, but we are helping someone new get started.
 

jnk

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In the past that was true for me, but we are helping someone new get started.

that person is not here anymore and has left the site . he thought fstop printing was a big waste of time, I'm starting to believe he was right
 
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faberryman

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In the past that was true for me, but we are helping someone new get started.

Do you teach printing to a lot of beginners? My experience is that if you start with someone new, they'll have only the vaguest idea what an f-stop is, and certainly couldn't recite the whole f-stops in sequence from f/1.4 to f/32, much less the half, third and quarter stops, so you'll likely lose them in the first five minutes. I guess if you have one of those fancy f-stop timers you can teach them to punch the right buttons but they won't have any idea what it means.

Of course, this is all theoretical. Virtually nobody prints anymore anyway. Darkroom 101 didn't make this semester at my community college. Another victim of COVID. Or high film and paper prices. So no new printers this semester.
 
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pentaxuser

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In the past that was true for me, but we are helping someone new get started.

Are we? Although he hasn't replied to my post asking him if he had already made his mind up about whether there was any value in fstop timing there might already be evidence about this. At the very least his relationship with Photrio might not be all it should for a new arrival seeking help

pentaxuser
 

nmp

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Are we? Although he hasn't replied to my post asking him if he had already made his mind up about whether there was any value in fstop timing there might already be evidence about this. At the very least his relationship with Photrio might not be all it should for a new arrival seeking help

pentaxuser

OP is on Restricted Access and all his posts are deleted by Sean.
 

Sirius Glass

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OP is on Restricted Access and all his posts are deleted by Sean.

Well, shall we not delve into how that came about?
 
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Geez-Louise! This is really a tempest in a teapot. It doesn't really matter how you figure out your exposure for the final print as long as you get good results. Streamlining the process is a good idea as long as we don't get overly hung up with details, calculations, etc., etc. And, I'm all for being able to visualize what exposure changes will look like in the final print. However, as Mark pointed out, the same exposure change (whether seconds, f-stops, percentages, etc.) will result in much different results with different contrast settings.

As I see it, one main concern is making a test strip that has (more) usable spacing. Using f-stop timing or percentages for the intervals will yield a more evenly-spaced result than just making the strip in multiples of the same interval. And, it allows one to cover a greater span of time. Making five 3-second exposures spans 15 seconds; making five exposures at 1/2-stop intervals spans a lot more, especially if your initial exposure is five seconds or more.

Personally, I use percentages, making test strips in 25% intervals. I make adjustments to print exposure in percentages as well and, when I get around to reprinting an image, I calculate the percentage of the base exposure I used for dodging and burning in the original print and apply that to the new base exposure time for the new print. That usually gets me close, but further refinements are almost always needed.

I don't think many great printers of the past (e.g., Ansel Adams et al.) used f-stop timing and their prints are just fine.

I like low-tech; I print with a metronome and think in percentages when it comes to exposure. I don't need a fancy timer or a table or to make any charts except maybe a 25%-interval sequence for test strips. Others swear by f-stop timing, others just use a fixed interval. Whatever works.

Doremus
 

faberryman

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I like low-tech; I print with a metronome and think in percentages when it comes to exposure. I don't need a fancy timer or a table or to make any charts except maybe a 25%-interval sequence for test strips. Others swear by f-stop timing, others just use a fixed interval. Whatever works.

This just hit me. I wonder if you could plug your microwave into an f-stop timer. Maybe get more accurate and consistent results heating up your coffee.
 
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nmp

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You are just more clairvoyant than I am.

Not clairvoyant. He asked vague and nonsensical questions like "I just built my darkroom and I am looking for the basic "dummies" book on enlargement." I am suspicious of any new person who is asking questions without giving details and contexts of what they are looking for. And then once the well meaning members as they are on this forum come back with their recommendations, OP shows little or no follow-up interest. I think members can do a better job early on to make the OP divulge more information and clarifications before jumping on to interpret their take on it.

:Niranjan.
 

Sirius Glass

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Not clairvoyant. He asked vague and nonsensical questions like "I just built my darkroom and I am looking for the basic "dummies" book on enlargement." I am suspicious of any new person who is asking questions without giving details and contexts of what they are looking for. And then once the well meaning members as they are on this forum come back with their recommendations, OP shows little or no follow-up interest. I think members can do a better job early on to make the OP divulge more information and clarifications before jumping on to interpret their take on it.

:Niranjan.

Excellent observations. I though it was a bit off but I gave him the benefit of withholding judgement.
 

M Carter

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Geez-Louise! This is really a tempest in a teapot. It doesn't really matter how you figure out your exposure for the final print as long as you get good results.
I agree. Our brains all work very differently. I made my first print in 1978, I did take a shot at f-stop but... my brain, salad colander that it is, is already really comfortable with timing. My print maps can be very complex (they're storyboards, really) since I do a lot of masking. I dial it in at, say, 8x10, and when I go to 16x20, I do the math and find the exposure factor, and scribble in new exposure, dodge, burn, and mask times based on that factor. I'd still have to re-write my print maps regardless of method used, but once I have my factor to go bigger (say it's 1.8x more exposure time), it's a few seconds with a calculator to fill in a fresh print map. Works for me, but you folks that swear by f-stop, I believe you! I believe you!!!

0v2I2vZ.jpg
 
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