Edge to edge focuser

[Philippe-Georges]

Linhof:

 

[snusmumriken]

Could you rephrase that question? One does not need a magnifier to see sufficient detail in an image, so I am not quite sure what you are asking.

I’ll try. You make the image as sharp as your eye can tell you under the enlarger. You seem to be saying that in the resulting print your eye will then see it as unsharp. I don’t see how that is possible.

I do my initial focusing wearing a relatively strong pair of reading glasses. But I'm often amazed just how much I'm off once I introduce the Peak magnifier.

I only have the Paterson jobs, but that’s what I meant about eyesight: my experience is that my eyes have always got it right. I stick the Paterson in place and there’s the grain. I understand what @MattKing is saying about fine grain (and presumably larger formats) making it necessary to focus on edges, so it’s relevant to say that I am only using 35mm.

 

[DREW WILEY]

It all depends. Sure, especially with a small film like 35mm significantly magnified, and if a relatively grainy film, and
a contrasty image, you're going to make out a certain amount of grain by simple means. But in principle, it is often more difficult than that, warranting better tools.

 

[MattKing]

You want the enlarger focus to be optimum, because if you miss that target, the miss will add blur where you don't want it to be.
The focus finders make it easier to see enlarger mis-focusing induced blur by magnifying it.

 

[Vaughn]

I’ll try. You make the image as sharp as your eye can tell you under the enlarger. You seem to be saying that in the resulting print your eye will then see it as unsharp. I don’t see how that is possible.


I only have the Paterson jobs, but that’s what I meant about eyesight: my experience is that my eyes have always got it right. I stick the Paterson in place and there’s the grain. I understand what @MattKing is saying about fine grain (and presumably larger formats) making it necessary to focus on edges, so it’s relevant to say that I am only using 35mm.

No, I am just saying there are other factors that have an affect on perceived sharpness. For example...I contact print making pt/pd prints and carbon prints. Using the same negative to make both types of prints, the carbon print usually will have a greater sense of sharpness than the pt/pd print. Part of this is due to my platinum image being on and in the surface of a lightly textured paper, while the carbon image (as I make them) sits on and above the surface of a glossy surface.

In photography, acutance describes a subjective perception of sharpness that is related to the edge contrast of an image. (simple wikipedia definition)

Relative to my platinum prints, the raised relief of my carbon prints increases acutance, the perception of sharpness, even behind glass.

Edit to add...I might not have answered your question well. With digital prints, getting up close can revel digital artifacts created to make the print appear sharper at a greater viewing distance...usually a little disappointing to see when the image otherwise draws one in. With enlarged silver gelatin, it might have enough contrast in the shadows to give an over-all feeling of sharpness at a greater viewing distance, but may not carry over when I put my nose to the glass, so to speak.

I am cursed, or blessed, with strong near-sightedness...so my taking off my glasses is like 'normal' folks using a magnifying glass. Perhaps that is why I appreciate sharpness the way I do.

 

[snusmumriken]

No, I am just saying there are other factors that have an affect on perceived sharpness. For example...I contact print making pt/pd prints and carbon prints. Using the same negative to make both types of prints, the carbon print usually will have a greater sense of sharpness than the pt/pd print. Part of this is due to my platinum image being on and in the surface of a lightly textured paper, while the carbon image (as I make them) sits on and above the surface of a glossy surface.

In photography, acutance describes a subjective perception of sharpness that is related to the edge contrast of an image. (simple wikipedia definition)

Relative to my platinum prints, the raised relief of my carbon prints increases acutance, the perception of sharpness, even behind glass.

I don’t understand. I don’t mean to be flippant, but no grain magnifier is not going to help contact prints, nor (in enlargements) the different image depth of platinum prints vs silver prints or carbon prints. I kinda feel those aspects of image sharpness are a different issue.

 

[DREW WILEY]

Yes, those are separate issues, just like the exaggerated pseudo-sharpness possible digitally. But true visual edge effect is not always microscopic, nor is microtonal gradation, both of which benefit from critical sharpness in the print. I won't go into the condenser versus diffuse source debate in this respect, or the added benefits of unsharp masking, or the almost archaic argument for using a blue filter along with the magnifier. Regardless, superior optics, both in terms of the enlarging lens and the grain magnifier itself, make life easier.

 

[MattKing]

In photography, acutance describes a subjective perception of sharpness that is related to the edge contrast of an image. (simple wikipedia definition)

that definition has got things turned around.
Acutance isn't the subjective perception of sharpness, sharpness is the subjective perception of edge contrast, which itself is acutance.

I don’t understand. I don’t mean to be flippant, but no grain magnifier is not going to help contact prints, nor (in enlargements) the different image depth of platinum prints vs silver prints or carbon prints. I kinda feel those aspects of image sharpness are a different issue.

The issue is that loss of sharpness - the subjective perception that is - tends to be cumulative.
Set the focus in the enlarger slightly off optimum, and the added blur cooperates with other sharpness reducing factors to create a total result.
The focus finders help optimize the enlarger focus itself, because they help you see when it is off.
One thing I've noted though, my need for help with that seeing is certainly greater than when my eyes were 50 years younger!

 

[Vaughn]

I don’t understand. I don’t mean to be flippant, but no grain magnifier is not going to help contact prints, nor (in enlargements) the different image depth of platinum prints vs silver prints or carbon prints. I kinda feel those aspects of image sharpness are a different issue.

Not writing specifically about grain enlargers, as the topic widened...so not understanding is understandable. All issues affect sharpness, though.

 

[snusmumriken]

The issue is that loss of sharpness - the subjective perception that is - tends to be cumulative.
Set the focus in the enlarger slightly off optimum, and the added blur cooperates with other sharpness reducing factors to create a total result.

Yes, OK, that makes sense to me. I’m still happy with my eyesight and cheapo tunnel-vision grain focusser though.

 

[Mal Paso]

Agreed. Too many prints, especially many digital prints, fall apart when viewed closely.

That may have been true in the past but modern sensors far surpass film in resolving power and have pushed lens makers to new levels of sharpness. Even the best older glass doesn't stand up to what lens makers are producing now.

My Epson printer is 4800 DPI and my 24x36mm sensor can provide 300 ppi on a 28 inch print. Basically 4x5 quality from a 35mm camera. Medium format will soon eclipse 8x10. A far cry from the 64K $36,000 Kodak/Nikon, my first digital experience.

That said I recently acquired a Peak Type 1 and really like it. I can see the grain in a 4x5 negative with it. I used a lesser quality magnifier early on that may have been dropped early on and never trusted them. You would have to put the Peak in a hydraulic press to change it's dimensions. None the less I ran tests on the Peak before putting it in service.

Although I paid $160 for mine but I've seen Peak Type 1s sell for $100 on ebay, you just have to hunt.

 

[DREW WILEY]

Mal - you're welcome to your own opinion, and I don't want to start yet another Digi vs Film feud.
NOBODY would mistake the vast majority of prints I make for anything digitally produced, either the color or black and white ones. Capture is only half the battle; and the cul-de-sac of digital capture is that it forces one to digitally print too, and for me, that would be a backwards step in quality. DPI is DPI. Film is film.

 

[Mal Paso]

Mal - you're welcome to your own opinion, and I don't want to start yet another Digi vs Film feud.
NOBODY would mistake the vast majority of prints I make for anything digitally produced, either the color or black and white ones. Capture is only half the battle; and the cul-de-sac of digital capture is that it forces one to digitally print too, and for me, that would be a backwards step in quality. DPI is DPI. Film is film.

I did not bring the subject up. I further don't think it has to be one or the other.

 

[cliveh]

that definition has got things turned around.
Acutance isn't the subjective perception of sharpness, sharpness is the subjective perception of edge contrast, which itself is acutance.

Why would acutance just be perception of edge contrast? Acutance applies across the whole image.

 

[MattKing]

Why would acutance just be perception of edge contrast? Acutance applies across the whole image.

It isn't, and that isn't what I said.
Acutance is entirely about edges though.

 

[cliveh]

Sorry Matt, as I may miss-understand you. When you mention edge, I thought you meant the edge of the image. Is that correct?

 

[MattKing]

Sorry Matt, as I may miss-understand you. When you mention edge, I thought you meant the edge of the image. Is that correct?

No, acutance refers to the measurable and observable contrast of rendered edges of the extremely fine details found in the scene.
For example, the edges of "grains of sand" seen at the beach.
Our visual systems are attuned to the edges, rather than the centre - the mostly subjective perception of sharpness is primarily related to how much contrast we observe in those edges, and that micro-contrast is essentially what acutance is.
One consequence of this is that grainy pictures often are perceived as being "sharper", even though grain tends to reduce resolution. The edges of that granularity enhance our perception of "sharpness". And as a result, film that has unusually fine grain often renders more smoothly but less sharp, even though there is more fine detail there.

 

[cliveh]

No, acutance refers to the measurable and observable contrast of rendered edges of the extremely fine details found in the scene.
For example, the edges of "grains of sand" seen at the beach.
Our visual systems are attuned to the edges, rather than the centre - the mostly subjective perception of sharpness is primarily related to how much contrast we observe in those edges, and that micro-contrast is essentially what acutance is.
One consequence of this is that grainy pictures often are perceived as being "sharper", even though grain tends to reduce resolution. The edges of that granularity enhance our perception of "sharpness". And as a result, film that has unusually fine grain often renders more smoothly but less sharp, even though there is more fine detail there.

Got you and yes I understand now. Sorry about the confusion.

 

[Vaughn]

That may have been true in the past but modern sensors far surpass film in resolving power and have pushed lens makers to new levels of sharpness. Even the best older glass doesn't stand up to what lens makers are producing now.

...

I agree that the quality of digital capture of light has sky-rocketed, but I was referring to large prints of all types and their tendency to break down upon close examination...which is more of a user-created situation, not necessarily a software/hardware issue. I won't say 'problem' because some people are creating images with set viewing distances in mind, or do not feel the need to satisfy those who stick their noses to the glass.. In some cases it is just a matter of the person needing to go too far with sharpening tools to learn how to back up and best work with an image. Painters make that decision all the time in deciding the type of brush strokes to use, etc. to create their image.

Using in-camera negatives, the raised relief possible with carbon printing process allows for an increased perception of sharpness that is created photographically (by the original unchanged negative), rather than altering the digital file of the image (possibly adding digital artifacts) to increase acutance. Both ways can work very well, both require good skills. There can be a significant height difference on the surface of the carbon print between two tones that creates a sharp 3D edge and an increased sense of sharpness. Sharpness is a tool to be used in the creation of an image -- but not a tool to just whack things with.

 

[GregY]

"not just a tool to whack things with." Nicely put Vaughn.

 

[Pieter12]

I agree that the quality of digital capture of light has sky-rocketed, but I was referring to large prints of all types and their tendency to break down upon close examination...which is more of a user-created situation, not necessarily a software/hardware issue. I won't say 'problem' because some people are creating images with set viewing distances in mind, or do not feel the need to satisfy those who stick their noses to the glass.. In some cases it is just a matter of the person needing to go too far with sharpening tools to learn how to back up and best work with an image. Painters make that decision all the time in deciding the type of brush strokes to use, etc. to create their image.

Using in-camera negatives, the raised relief possible with carbon printing process allows for an increased perception of sharpness that is created photographically (by the original unchanged negative), rather than altering the digital file of the image (possibly adding digital artifacts) to increase acutance. Both ways can work very well, both require good skills. There can be a significant height difference on the surface of the carbon print between two tones that creates a sharp 3D edge and an increased sense of sharpness. Sharpness is a tool to be used in the creation of an image -- but not a tool to just whack things with.

Not that long ago, I went to an exhibition of Rock'n'Roll photos that included some that were in the 48-60" range, with crisp grain that practically poked your eye if you got close. These were 35mm photos taken form the stage during performances and rehearsals with pushed film and just the stage lighting. The grittiness and contrast gave them an energy that really delivered some of the concert experience. If the grain were too fine or soft, I don't think they would have that impact.

 

[pentaxuser]

That said I recently acquired a Peak Type 1 and really like it. I can see the grain in a 4x5 negative with it.

My understanding is that the Peak is no better at focusíng on grain than the Paterson ie its magnification is no better. Where it scores more highly is in being able to edge focus which the Paterson cannot do

pentaxuser

 

[DREW WILEY]

It's way better in several respects. Paterson is an odds n' ends camera store brand offering numerous handy darkroom aids. But Peak specializes in a range of high end optical gear, including the equipment many Optometry clinics rely on. The ease of focus in this case is due to the superior optics and overall precision of the Peak 1 unit. You can even obtain precisely matching replacement front surface mirror if necessary. And you can really begin to appreciate the superior construction when you combine it with a high-end true apo enlarging lens projecting color neg film, which can be harder to focus on than black and white grain.

 

[Don_ih]

Paterson is an odds n' ends camera store brand offering numerous handy darkroom aids.

In this instance, the construction of the device is simple mathematics. If it works, it works. There's no evidence mine doesn't work. I have three grain focusers - they all agree - two are Paterson, one is an older cast-iron one of unknown brand (or I don't recall). While Paterson may be just someone who makes "handy darkroom aids", they wouldn't continue selling very many unless they actually worked.

The only thing it doesn't do is leave the middle of the projection. But that ultimately doesn't matter for the vast majority of people and uses.

 

[DREW WILEY]

The Peak looks and feels like a fine instrument, which it is. I wish it was the first grain magnifier I ever bought. Paterson is a helpful supplier of moderate cost darkroom accessories. No complaints there. And certainly not everyone can justify the expense of a Peak 1 unless they run into a good deal on a used one (which does happen).
But if you're trying to optimize your enlargement protocol, seemingly little benefits can cumulatively add up to an overall better end result.