Grain enlarger/focuser

[Omid_K]

When focusing, should I place the grain enlarger on a sacrificial piece of paper or directly on the easel? Essentially I’m wondering if they are calibrated to take into account the millimeter or so of paper thickness. I know some paper is thicker than others which is what got me wondering this. At the same time I’m thinking that the plane of focus may be deep enough to render this question moot.



Thanks,
Omid

 

[jim10219]

Yes, you should place it on some paper. I use several sheets of normal paper that equal the thickness of the photo paper I'm using so I don't have to sacrifice anything. You could use some old photo paper that you saved from the trash.

Though to be honest, the thickness of the paper isn't much and I usually stop down the lens a bit anyway, so it probably doesn't make much of a difference whether I place the focuser on paper or not. But I've found with darkroom work, consistency and accuracy are keys to producing good work, so I always use a sheet of spacer paper since it's easy and quick to do.

 

[Jim Jones]

I've always placed the grain enlarger directly on the easel. Calculations I did years ago suggested that the depth of focus on the easel was sufficient to cover any focus error this caused. However, for your own piece of mind you might experiment with scraps of the thickest paper you use. First focus on the easel, and without refocusing the enlarger, add pieces of that paper under the grain enlarger until there is noticeable unsharpness through the grain enlarger. Then you will know just how much latitude your enlarger, paper, and grain enlarger have. Let the rest of us know the results.

 

[Pieter12]

I focus and put the grain focuser on a rejected print, face down in the easel. I also draw even margins (or uneven if that's what I want, such as a square print) on the back of that same print to allow me to easily adjust the blades.

 

[Bill Burk]

I used to put it on a piece of paper but lately I don’t bother. Probably from something I read here, like it’s the lens to film distance that’s critical and the focuser takes care of that. My son, on the other hand, prefers not to use the contraption and eyeballs it.

 

[Chan Tran]

I used to put it on a piece of paper but lately I don’t bother. Probably from something I read here, like it’s the lens to film distance that’s critical and the focuser takes care of that. My son, on the other hand, prefers not to use the contraption and eyeballs it.

Yup! When I was in my 20's there was absolutely no need for the grain focuser. In fact it's easier to see the grain with the naked eyes.

 

[AgX]

If one does not trust in calculations, one just has to focus the enlarger in boths stands (w. and wo. paper). Likely the focus difference would be too small to set.
Altrernatively one may refocus the eypiece of the focuser for both cases, to see for a difference.

 

[MattKing]

The depth of focus at the easel means that the paper won't affect the accuracy of focus.
Sometimes the paper helps by making it easier to see and therefor check the cropping.

 

[AgX]

Sometimes the paper helps by making it easier to see and therefor check the cropping.

Am slow on the uptake again. What do you mean by that? Finding the borders of what still has to be exposed and be sufficiently sharp?

 

[Ian C]

This is essentially a restatement of post #8.

Many enlarging papers are about 0.0115” or about 0.29 mm in thickness. This can vary somewhat depending on the particular paper.

In theory, the thickness of a sheet of scrap paper of the same type as you're using under the grain magnifier will help you to perfect the focus. In practice, it makes no difference. For example, when making an 8” x 10” full-frame enlargement from a 35 mm negative with a 50 mm lens the required magnification is about 9.1X.

At that magnification, and with the aperture set at f/5.6, the depth of focus about the image plane is 29.9 mm using circle-of-confusion diameter 0.029 mm. About half of the depth of focus lies above, and half lies below the image plane. Whether the grain focuser is resting on a sheet of enlarging paper or not won’t make a discernable difference in the result.

The main benefit of using an upside-down scrap print in the easel is that it makes rough focusing easy due to the reflectance of the white paper. This makes it easier to see the projection. It also makes sizing and composing the image (adjusting the position of the easel) to fit the projection easy.

 

[tezzasmall]

I too don't bother with a sheet of paper on the printing easel. I tried putting a sheet of paper on the easel years ago and it made no difference to focusing through an aid but despite this, this question still circulates every once in a while, with votes on each side. Therefore it's really a matter of the OP trying it for themselves to settle their own curiosity.

Only yesterday, when I was last in the darkroom, did I once again realise that there was quite a big amount of turning of the focusing knob, both ways, before it went out of focus through a magnifier i.e. there must be quite a large bit of dof, even with my (Nikon) F4 lens wide open for foucusing and sometimes even printing.

As for focusing by eye, I had to do it recently with a VERY dense negative and was happy with the final print. In this instance I could not see any grain at all through the magnifier, hence the need to use ones eyes, which in turn surprised me at the grand age of 58.

There has also been a thread quite recently about using the blue filter with some Peak focusing aids, which again has two camps of thought, but again, I could see no difference in the focusing with and without it.

Terry S

 

[MattKing]

Am slow on the uptake again. What do you mean by that? Finding the borders of what still has to be exposed and be sufficiently sharp?

I have easels with yellow surfaces, and easels with dark grey surfaces.
If I have a sheet of paper in the easel, the projected image is easier to see, and therefore it is easier to see if the easel is properly positioned.

 

[Bill Burk]

Am slow on the uptake again. What do you mean by that? Finding the borders of what still has to be exposed and be sufficiently sharp?

Haa no. Simpler than that.

If you put a blank sheet of paper on the easel it will be easier to aim the whole picture (compose).

 

[Bill Burk]

I have easels with yellow surfaces, and easels with dark grey surfaces.
If I have a sheet of paper in the easel, the projected image is easier to see, and therefore it is easier to see if the easel is properly positioned.

This!

 

[pentaxuser]

Yup! When I was in my 20's there was absolutely no need for the grain focuser. In fact it's easier to see the grain with the naked eyes.

I had no idea that it was possible to see grain, of the kind that a grain focuser reveals, with the naked eye, even for people in their 20s . The Paterson grain focuser I use must magnify the negative projection by maybe 20x or more and I would have never thought that the naked eye had the facility act like this.

That isn't to say that the naked eye in excellent order can't as near as makes no difference focus sufficiently sharply to make a grain focuser unnecessary. That may be possible, I just don't know

pentaxuser

 

[AgX]

I have easels with yellow surfaces, and easels with dark grey surfaces.
If I have a sheet of paper in the easel, the projected image is easier to see, and therefore it is easier to see if the easel is properly positioned.

My fault. I had the advanced version of focuser in mind that works with a mirror, thus not with reflection from base or paper

 

[Sirius Glass]

I always place the same type of paper under the grain focuser even though I am not sure it makes a difference.

 

[RalphLambrecht]

When focusing, should I place the grain enlarger on a sacrificial piece of paper or directly on the easel? Essentially I’m wondering if they are calibrated to take into account the millimeter or so of paper thickness. I know some paper is thicker than others which is what got me wondering this. At the same time I’m thinking that the plane of focus may be deep enough to render this question moot.



Thanks,
Omid

as you suspected,the depth of focus eliminates this issue;there is absolutely no need for an extra piece of paper under the grain focuser;none!

 

[Bill Burk]

I had no idea that it was possible to see grain, of the kind that a grain focuser reveals, with the naked eye, even for people in their 20s . The Paterson grain focuser I use must magnify the negative projection by maybe 20x or more and I would have never thought that the naked eye had the facility act like this.

That isn't to say that the naked eye in excellent order can't as near as makes no difference focus sufficiently sharply to make a grain focuser unnecessary. That may be possible, I just don't know

pentaxuser

My son doesn’t care, you know some people aren’t seeking perfection in their results. Some of his prints I can tell he obviously was out of focus on the easel. If I were his teacher I might say something but it wasn’t my place to say.

I care about sharp focus at the easel, but I know at times that by eye I can sometimes focus as sharply as would be necessary. If I were at a school darkroom, I wouldn’t quit for the day if I couldn’t find a grain focuser.

 

[Pieter12]

My son doesn’t care, you know some people aren’t seeking perfection in their results. Some of his prints I can tell he obviously was out of focus on the easel. If I were his teacher I might say something but it wasn’t my place to say.

I care about sharp focus at the easel, but I know at times that by eye I can sometimes focus as sharply as would be necessary. If I were at a school darkroom, I wouldn’t quit for the day if I couldn’t find a grain focuser.

Speak up, everyone should care. Otherwise why bother? Grain focus is not a question of taste or artistry (image focus in the camera can be). It doesn't take much extra effort to do it right.

 

[MattKing]

It was a lot easier when I had younger eyes - I could get the focus really close without any focus aid, and then use the grain focuser to make a tiny adjustment to get it right on.
Which is particularly nice if the enlarger's focus control is a long way above the easel.

 

[jim10219]

I had no idea that it was possible to see grain, of the kind that a grain focuser reveals, with the naked eye, even for people in their 20s . The Paterson grain focuser I use must magnify the negative projection by maybe 20x or more and I would have never thought that the naked eye had the facility act like this.

That isn't to say that the naked eye in excellent order can't as near as makes no difference focus sufficiently sharply to make a grain focuser unnecessary. That may be possible, I just don't know

pentaxuser

I'm in my 40's and I can easily see the grain without a grain focuser when enlarging most 35mm film onto 8x10 or larger. To be honest, I kind of thought most people could. I do have slightly better than average near vision though (something like 15/100 vision). That may explain why I keep saying 8x10 is about the limit for 35mm film enlargements, and keep getting told by other people that there must be something wrong with my technique if those prints seem too grainy to me.

 

[AgX]

All these advices and those COC's are based on a standard enlargement and standard vision.

 

[Hilo]

Nice thread !

It should not matter, but I place a sheet of paper anyway. And before placing the unexposed sheet I take the first sheet out of the easel.

I have no technical knowledge about the following, but was taught it by a b/w printer in Paris around 1980: I try to use the grain focuser as close to an edge as possible. This because the grain in the middle of the image seems to follow in being sharp. The other way around (focus in the middle) I have had less grain sharpness in the corners, but not always. This is mostly about printing 135mm negatives on 50x60cm (20x24in) with different enlargers, Focomats 1c and 2c, Valoy II and Durst L1000. But also using any negative size up to 4x5. I use good six elements lenses.

Of course it is not always easy to place the focuser near a corner. It depends on the image and some focusers are better at it than others.

 

[Doremus Scudder]

I've always got a scrap piece of photo paper on the easel, upside down, so I can view the image on the white paper instead of the yellow of my Saunders easels. So, I place my grain focuser on that to focus. And, why not be as accurate as possible, even if the difference is negligible?

Best,

Doremus