Tonality in MF vs 35mm

[David Goldfarb]

I don't think of it as a "sweet spot" so much, but I agree with Roger about a maximum enlargement factor of about 5x or so and a preference for 2x-3x (or a contact print).

I don't print really big that often, so I'm not sure if there's another factor for big prints, but it's an interesting idea. I've certainly seen big prints that are enlarged way beyond 5x that I've liked. I suppose that the idea of two "sweet spots" would have to do with the difference between a print viewed in the hand or on the wall at close range as opposed to the kind of print you have to step back to see.

 

[FrankS]

Thanks Roger for checking in here at RFF even though you have some of those new Summarits to play with!

So you're saying that it is a half-tone effect that comes into play at larger sizes that compensates (in a range of larger enlargements) for the increasing grain size?

Thanks David, you are a printer I admire and value your input. Roger has talked about 2 sweet spots: smaller enlargements up to 4x6 due to lack of grain, and then again around 12x18inches, due to a half-tone effect.

 

[raid]

Dear Frank,

This is one reason, I believe, why Delta 3200 can give such sweet tonality in quite small prints: the half-tone effect comes in quicker at all densities with such big grain.


Cheers,

Roger

Dear Roger,
Thank you and the rest of the people who have contributed to this thread. It is very informative.

Here is a photo taken [not with Delta 3200] with TMZ3200:
http://www.rangefinderforum.com/photopost/showphoto.php?photo=67360

I like the extra grain.

Cheers,

 

[Finder]

Can someone explain "half-tone effect." I have no idea what it is - I know what half-tone printing is, but that has nothing to do with this topic. None of my technical books has anything on this either and a search produces nothing related.

 

[Finder]

I don't think of it as a "sweet spot" so much, but I agree with Roger about a maximum enlargement factor of about 5x or so and a preference for 2x-3x (or a contact print).

Well, after seeing a number of exhibits, especially Salgado exhibitions, I can't see that 5x is a limit to enlargements. I certainly has not been my experience. You really cannot get a print from 35mm bigger than 5x7 that looks good?

 

[Roger Hicks]

Thanks Roger for checking in here at RFF even though you have some of those new Summarits to play with!

So you're saying that it is a half-tone effect that comes into play at larger sizes that compensates (in a range of larger enlargements) for the increasing grain size?

Thanks David, you are a printer I admire and value your input. Roger has talked about 2 sweet spots: smaller enlargements up to 4x6 due to lack of grain, and then again around 12x18inches, due to a half-tone effect.

Whart I'm saying is that there are 3 stages.

Stage 1: no half-tone effect, contact-print or near contact-print tonality.

Stage 2: half tone effect in some areas and not others, tonality goes to hell.

Stage 3: half tone effect in all tones, tonality improves again -- though not the same as stage 1, and (in my opinion and I suspect David's as well) not as good, though still better than stage 2.

So it's not so much a 'sweet spot' as a 'dead zone', at any enlargement above or below which the tonality is better.

Cheers,

Roger

 

[David Goldfarb]

Well, after seeing a number of exhibits, especially Salgado exhibitions, I can't see that 5x is a limit to enlargements. I certainly has not been my experience. You really cannot get a print from 35mm bigger than 5x7 that looks good?

You didn't read the second part of my post. To my taste, I don't like to enlarge more than about 5x, and I like contact prints, so I own some big cameras for that purpose. I can make an enlargement that other people will like that falls outside these parameters, but when I print for myself, I have my preferences.

But to rephrase what I said in the second paragraph, I have seen large prints that I like, and I think Roger is on to something with the idea that there is probably an ideal enlargement factor for big prints as well as for small prints, and some range in the middle that isn't as attractive, and it is interesting to think about why that might be.

 

[Finder]

But to rephrase what I said in the second paragraph, I have seen large prints that I like, and I think Roger is on to something with the idea that there is probably an ideal enlargement factor for big prints as well as for small prints, and some range in the middle that isn't as attractive, and it is interesting to think about why that might be.

I think the answer is easy. It is simply viewing distance. I take it the "half-tone effect" is just seeing granularity. That has nothing to do with print size by itself. It is also related to how far you are away from the print. Keep the viewing distance proportional to the print size and visually nothing changes no matter the enlargement factor.

 

[Roger Hicks]

I know what half-tone printing is, but that has nothing to do with this topic. .

Yes, it does, actually. It's the difference between the 'average' grey you get from a mixture of dark grain and light areas in between -- just as with a half-tone reproduction -- and the continuous grey you get in a contact print (or very small enlargement) or with a moving paper under the enlarger.

Repeat the experiment I described in an earlier post (19) and you can verify its existence for yourself.

As for your assertion that the half-tone effect is 'easy' or a matter solely of viewing distance or about 'seeing granularity', the argument is precisely that you DON'T see it, just as you don't see the dots (or are not aware of them) in a half-tone reproduction.

Of course it is distance-dependent, but that is so obvious I though no need to mention it. I repeat my belief that at up to around 2-4x you can produce an enlargement substantially identical to a contact print, i.e. one that will show no half-tone effect at any distance, no matter how closely examined. Beyond 8-10x, again at close viewing distances, the half-tone effect is visible eveywhere, and the tonality recovers.

As I took pains to point out, there is plenty more -- such as 'sparkle' -- that affects our perception of tonality, but the half-tone effect exists and is, I believe, neither irrelevant nor (until it is explained) obvious.

Finally, you don't have to take anything I'm saying on faith. Try it. If you don't see it, fine: it's irrelevant to you. All I'm saying (and I think others have agreed) that my own experience suggests the half-tone effect at middling enlargement sizes (5-9x or 4-10x or whatever it may be) as a significant contributing factor to tonality.

Cheers,

Roger

 

[keithwms]

But chemically and physically, the same range of tones is recorded in both 35mm and MF format or even LF. It has to be, unless the MF and LF films are made from a different emulsion formula.

If I understand your comment correctly, you are saying that films in all formats have the same Dmax & Dmin, and that is what you mean by range of tones. If that's what you mean, then I agree.

However, I think Dmax and Dmin are actually not so critically important to our overall perception of 'natural' tonality. How "continuous tone" a photo is, and the smoothness of tonal transitions... that depends very much on the format size. To put it simply, smaller formats have a greater tendency to posterize transitions. And this is what I think is often lost in discussions of format size: it is not Dmax and Dmin that matter so much, it is the tonal transition from one to the other and how continuous that is.

There is a very simple thought experiment to demonstrate what I mean. Imagine that film is nothing but an array of pixels that can register only as pure white or pure black upon exposure. Obviously the number of intermediate greys you can get from an ensemble of pure black and white pixels depends very much on the pixel number.

Of course in real film (or digital) the grains/pixels do not register as pure white or black, but nevertheless the simple logic holds.

Regarding posterization, it can give the appearance of higher edge sharpness. Another thing is that we can of course interpolate a small-format image, in which case no resolution is gained, but the issue of tone posterization is mostly solved and the resulting image can have a more continuous tone impression. Of course the issues of noise/grain versus signal are much larger in the limit of smaller format sizes, and the noise/grain sets a hard limit on what transitions can be meaningfully interpolated and the acceptable enlargement factor.

Probably everything that I just said is completely obvious. 🙄

Anyway, TV and our computer screens have trained us to accept posterization as a fact of life. And unfortunately certain magazines have allowed posterization to creep in, so I am afraid that an appreciation for the tonality of the larger formats is eroding over time. We need to have more MF/LF print shows! We need to train people to expect more than what they see on a TV set, even an HD one!

 

[Tuolumne]

Is all of this only true of wet darkroom prints, or is it also true for inkjet digital prints?

/T

 

[Finder]

Yes, it does, actually. It's the difference between the 'average' grey you get from a mixture of dark grain and light areas in between -- just as with a half-tone reproduction -- and the continuous grey you get in a contact print (or very small enlargement) or with a moving paper under the enlarger.

Repeat the experiment I described in an earlier post (19) and you can verify its existence for yourself.

As for your assertion that the half-tone effect is 'easy' or a matter solely of viewing distance or about 'seeing granularity', the argument is precisely that you DON'T see it, just as you don't see the dots (or are not aware of them) in a half-tone reproduction.

Of course it is distance-dependent, but that is so obvious I though no need to mention it. I repeat my belief that at up to around 2-4x you can produce an enlargement substantially identical to a contact print, i.e. one that will show no half-tone effect at any distance, no matter how closely examined. Beyond 8-10x, again at close viewing distances, the half-tone effect is visible eveywhere, and the tonality recovers.

As I took pains to point out, there is plenty more -- such as 'sparkle' -- that affects our perception of tonality, but the half-tone effect exists and is, I believe, neither irrelevant nor (until it is explained) obvious.

Cheers,

Roger

Well Roger, I have made contacts and at a close view I can see granularity. I have no problem in seeing granularity in an 8x10 from a 4x5. Also, when I step back to where granularity is not percieved, there is no tonal change in the image - I assume it is grain not being resolved changes things.

I still have no reference to your "half-tone effect." I know human perception will see a moving black and white area as different tones or colors. I have never known a densitometer give different readings because of the granularity of the target. I am going into the darkroom soon and if I find a clear piece of film, I will give your test a whirl.

 

[Finder]

Is all of this only true of wet darkroom prints, or is it also true for inkjet digital prints?

/T

All of what? About viewing distance, it is true.

 

[Roger Hicks]

Is all of this only true of wet darkroom prints, or is it also true for inkjet digital prints?

/T

I don'tr know enough about inkjets to say anything. In a sense, they're always half-tones -- but with grey inks, the effects must be different. But yes, I've been talking exclusively about what I persist in regarding as 'real' (wet) B+W prints.

Cheers,

Roger

 

[Sparrow]

Is this Tonality what I know as Tonal gradation? the dynamic change between the lightest and darkest shades in the print, or something different

 

[FrankS]

I love this place. Thank you all for your input!

 

[Roger Hicks]

Well Roger, I have made contacts and at a close view I can see granularity. I have no problem in seeing granularity in an 8x10 from a 4x5. Also, when I step back to where granularity is not percieved, there is no tonal change in the image - I assume it is grain not being resolved changes things.

I still have no reference to your "half-tone effect." I know human perception will see a moving black and white area as different tones or colors. I have never known a densitometer give different readings because of the granularity of the target. I am going into the darkroom soon and if I find a clear piece of film, I will give your test a whirl.

Can't help you on a reference. I learned about this from an Ilford researcher who has since left the company.

I am astonished that you can see grain in a contact print, but if you can, you can. What film are you using? And what developer?

No, a densitometer won't give different readings. Why would it? It is giving average reflection density of the area read, whether that is an even grey, a half-tone grey or indeed half solid black and part solid white.

Clear film won't work: it has to be a modest density. And, as noted elsewhere, the effect varies with exposure (more exposure = bigger grain, except of course with chromogenics). Try something like 0,30 and 0,60 above fb+f.

Forgive me if I seem thin skinned, but you seem to be proceeding on the basis that I am making this up. Why would I do so? Someone asked a question; I gave an answer, based on a mixture of experience and knowledge. I do not have a lot invested in whether or not people believe what I say. As the Buddha himself said, if what I say is of no use to you, set it aside. Others may find it useful or at least interesting.

Cheers,

Roger

 

[FrankS]

As the Buddha himself said, if what I say is of no use to you, set it aside.

Very smart man!

 

[Finder]

Forgive me if I seem thin skinned, but you seem to be proceeding on the basis that I am making this up.

I don't think you are making it up. I am just not sure the cause is what you say it is. Partly because I have not experienced it and partly because I can find not published information on it. I think your underlying response to print size, what you call the "half-tone effect," is something else. I have seen enough images, but I am not seeing what you are seeing in them, at least not in the terms you state. So I am assuming it is some other known factor causing the same thing and I am trying to put my finger on it.

 

[Roger Hicks]

I don't think you are making it up. I am just not sure the cause is what you say it is. Partly because I have not experienced it and partly because I can find not published information on it. I think your underlying response to print size, what you call the "half-tone effect," is something else. I have seen enough images, but I am not seeing what you are seeing in them, at least not in the terms you state. So I am assuming it is some other known factor causing the same thing and I am trying to put my finger on it.

Fair enough. I'm not sure either. I shall be delighted if you can produce a better explanation, because the half-tone effect -- which is demonstrable, as I say -- has always struck me as inherently a bit unlikely as a major determining factor in tonality.

It's just that I have never found anything more believable. Nor has anyone else I have discussed it with. All agree that it could be the case; there is rather more doubt as to whether it actually is the case. The name 'half tone effect' is borrowed wholesale from my chum who used to be at Ilford. We remain in contact; maybe I'll call him over the week-end. I think the original research was done in the 1940s but I may be mis-remembering.

Let's try another slant. Do you see a fairly sudden deterioration in tonality after about 3-5x, as David and I do, or do you see a steady deterioration with increasing magnification? And have you found that (say) a 12x18 inch print off 35mm may well look better than an 8x12?

It may also be that there are significant perceptual differences here, too: the 'wiring' of the brain in infancy is a fascinating field of research, i.e. it may be that David and I see one thing, and you see another.

Cheers,

Roger