Normal file size????????

[rdenney]

Are you saying that there is actually a benefit to rezzing up? Or down? Why throw away lots of pixels of information? It doesn't make sense to me... sharpening seems to work fine at whatever size...

I never resample my original scan. Any sharpening I do to the original scan is done solely to correct the effects of the scanning (or capture) process.

The only time I resample is when I'm going to display it at a much different size (always smaller) than the original scan. I've never had any luck up-rezzing photos and having them look worth a darn, and I would rather just print within the capabilities of the scanner or digital camera.

But consider what Frank said. He used an extreme example--a web display--to illustrate the point. A monitor has a screen resolution in the vicinity of 100 pixels/inch. To give that image just a hint of more detail than meets the eye, I have to sharpened it. I set my unsharp masking parameters to achieve the effect. But those parameters are measured in pixels, in Photoshop. For web display, I may be reducing the linear resolution from 8000 to 800 pixels. The sharpening I did at the original resolution may have a radius of some fraction of a pixel, and that sharpening effect will vanish utterly when I display it on a monitor--it will be a fraction of a fraction of the smallest thing visible on the screen.

So, I need to sharpen it again, this time at the display resolution, so that my settings have relevance on the display device. This time, I want a sharpening effect not to correct fuzziness caused by the scanner optics or the AA filter in a digital camera, but rather to achieve a particular look in the final print. Thus, the settings for that sharpening process have to relate to pixels that are actually relevant at display resolution. Since the main parameter in sharpening is the radius, and since the radius is measured in pixels, I have to resample the image first, so that the sharpening I'm doing for targeting purposes has visual relevance.

A screen display is an extreme example. But extreme examples often lay at the other end of a continuum. If I have a file that is 8000x10,000 pixels, and I want to print it on my Epson at 8x10 inches, the file will have a resolution of 1000 pixels/inch on the print. Any sharpening I do with a radius of a fraction of a pixel is so much wasted effort--it will never be seen. But I want that 8x10 print to have a little more zip than a 16x20 print, because of how people will look at it. So, I first downsample a copy of the file that I'm targeting for an 8x10 print to something like 3600 pixels wide, for a pixel density at print size of 360 pixels/inch. I'm not worried about aliasing the printer resolution--that is too small to see in any cased, though some claim to see it. I'm worried about the sharpening that I do having the visual effect that I want, for an 8x10 print. After resampling the image to be 3600 pixels wide, the sharpening settings (particularly radius) that are in pixel dimensions now mean something relevant at that print size.

As I said before, most of my large-format images have such an abundance of local contrast that the final print doesn't need any of that at any reasonable print size. So, I may not apply sharpening at all during targeting. It happens a lot more when making prints from my digital camera. But what about feathering a selection? That's also measured in pixels. Let's say my experience tells me that at 360 ppi in the print, I need a feather of, say, 10 pixels to provide a visibly smooth gradation rather than a harsh edge or bright line. If I was working with a file ten times my display resolution, I'd have to set that feature to 100, and then it would still be wrong for a print of different size. I might want the narrowest feature I can use that isn't swallowed up when being downsampled either by the printer or for web display. Jim says he doesn't worry about it, and that's why he's had to answer a question or two about the bright edges on his sky selections. I know those are smooth and gorgeous at print size, but he would need a thicker feather to achieve the same effect at web display size.

By resampling the target file before making those changes, I can tailor their settings for print resolution relevance rather than having to do pixel arithmetic in my head.

I used to work with original scans, setting them up for the biggest print I intended to make. But then I bought an Epson 3800, and suddenly my biggest print got bigger. The result is that I have had to rescan some images for larger prints. Had I stored my original scans with corrective adjustments only, all I would have needed to do was make another copy for the new target size, and then make targeting adjustments for my new printer at that size. Would have saved a lot of time with those images.

I've made plenty of prints at much higher than 360 ppi resolution at the printer, and let the printer sort it out without issue. But those were prints that didn't need those pixel-based effects to look right. And I'm also giving the impression that I consider this more carefully and in more detail than I really do. The larger the original scan (and the larger the film being scanned), the less any of this seems to matter in the final print. I've made lots of pictures that I like with a 6-MP APS-C DSLR, and those need very careful, display-resolution sharpening.

Rick "sometimes working right at the original file's limits" Denney

[Lenny Eiger]

I never resample my original scan. Any sharpening I do to the original scan is done solely to correct the effects of the scanning (or capture) process.

The only time I resample is when I'm going to display it at a much different size (always smaller) than the original scan. I've never had any luck up-rezzing photos and having them look worth a darn, and I would rather just print within the capabilities of the scanner or digital camera.

I agree.

But consider what Frank said. He used an extreme example--a web display--to illustrate the point.

I'm not really concerned with web display and downsizing to that level. I don't disagree... but I'm not even looking at it.

If I have a file that is 8000x10,000 pixels, and I want to print it on my Epson at 8x10 inches, the file will have a resolution of 1000 pixels/inch on the print. Any sharpening I do with a radius of a fraction of a pixel is so much wasted effort--it will never be seen. But I want that 8x10 print to have a little more zip than a 16x20 print, because of how people will look at it. So, I first downsample a copy of the file that I'm targeting for an 8x10 print to something like 3600 pixels wide, for a pixel density at print size of 360 pixels/inch.I'm worried about the sharpening that I do having the visual effect that I want, for an 8x10 print. After resampling the image to be 3600 pixels wide, the sharpening settings (particularly radius) that are in pixel dimensions now mean something relevant at that print size.

This is the part that doesn't make sense to me. I agree that as you go up, there are multiple reasons, both in the printing technology and the visual characteristics of the eye, that prints usually need a little more zip. However, I don't know that sharpening is the tool to address it. I would just use a slight adjustment in the main curve...

There seems to be no reason to me to toss the info, going from your example of 10K pixels to 3600. Your math is off on the example, a 20 inch print at 360 would require 7200, but I get what you are trying to say.

I think your idea is based on an assumption that there is a difference in pixel dimensions for a certain size - on the paper. perhaps you are saying there is a standard printing dpi that was all the printer could do. Suffice it to say, I am not sure I agree with those assumptions.

The 16x20 at 10K pixels, or 26K pixels, what I usually print at, might very likely have more definition than the smaller, targeted size, if you are printing in b&w with b&w inks, for example. There is a clear benefit to my eyes of having 450 dpi or so, and possibly up to 720 or so... and I see no reason to throw away data. I think I should sharpen to the pixels I have and send them to the printer. If I need more "zip" I read that as contrast, rather than sharpening...

I guess I don't see issues with "pixel-based" effects. I think I would have to see two prints side by side to see the difference. Of course, I'm not sharpening much at all so maybe my system doesn't show it as ccd-based systems would. If I needed a lot of sharpening, for a digital camera, for instance, maybe I would see what you are seeing...

Lenny

[rdenney]

Lenny, I would bet that if you and I were considering the same sets of images, files, and desired displays, we would gravitate to the same basic decisions. And if we didn't, I'd be more apt to question myself than you. But we might get there from different starting points. I often print my big scans at 720, though I have not done enough testing to know it makes a difference. Those are the sorts of images that don't seem to need sharpening during targeting. That sort of resolution headroom hasn't been that common for me until going back to bigger formats.

Rick "often trying to make prints look good at 240 ppi" Denney

[Lenny Eiger]

But we might get there from different starting points.

This is absolutely true. There is so much to test. Then things change, a new developer technique arises or something you missed. It never occurred to me to pour exhausted Pyro out of my Jobo and pour in some fresh developer in the middle of the cycle. Altho' I am now head and shoulders into the Xtol, and currently enjoying it, I'm almost positive it would have worked. I was messing with the formula, adding activator and other developing agents and going nuts. I felt like an idiot when someone here mentioned the obvious solution - that I missed totally.

I also remember when I fist got started with photoshop -= 5 different people told me that I had to do x - or i would fail. Of course, they all disagreed. so at least 4 of them were incorrect. I think many of us do get to a good, or in some cases, great print, coming at it from entirely different angles.

Lenny

[bob carnie]

Can I take credit for the two dev, in pyro since this has been our working method since day one, to battle exhausted developer. And yes it does work.

This is absolutely true. There is so much to test. Then things change, a new developer technique arises or something you missed. It never occurred to me to pour exhausted Pyro out of my Jobo and pour in some fresh developer in the middle of the cycle. Altho' I am now head and shoulders into the Xtol, and currently enjoying it, I'm almost positive it would have worked. I was messing with the formula, adding activator and other developing agents and going nuts. I felt like an idiot when someone here mentioned the obvious solution - that I missed totally.

I also remember when I fist got started with photoshop -= 5 different people told me that I had to do x - or i would fail. Of course, they all disagreed. so at least 4 of them were incorrect. I think many of us do get to a good, or in some cases, great print, coming at it from entirely different angles.

Lenny

[sanking]

Can I take credit for the two dev, in pyro since this has been our working method since day one, to battle exhausted developer. And yes it does work.

Depends on when you started doing it. But I am betting you are not the first person to use this method. I recall an article on splitting the developer in two parts and discarding the first part after half of the development time that was published in View Camera magazine the very early 1990s. And of course, this is a fairly primitive way of dealing with the problem. A much simpler method is to just add a bit more sulfite to the working solution, as described in the Film Developing Cookbook of Anchell and Troop which was published in 1998. Or you could also add a bit of ascorbic acid, which as the method used by Harald Leban in the Rollo Pyro formula but it work perfectly well with PMK as well.

Course, even if you were not the first to use the method there is nothing to prevent you from claiming that you were. There are many people who believe they are the first to use coating rods to apply emulsions to film, and/or carbon tissue, in spite of the fact that this is well documented in literature from the 1800s.

Sandy

[bob carnie]

Ok so you screwed up my place in history
I actually know the exact date as we destroyed my future business partner wedding film with a exhausted pyro run. November 1997 , from that date forward we started to split the dev run into two separate litres of pyro.
I am still amazed to this date that he eventually decided to get into business with me.
I suppose the Academy Award Crying jag I performed convinced him that I was sorry for spoiling his special day.

Depends on when you started doing it. But I am betting you are not the first person to use this method. I recall an article on splitting the developer in two parts and discarding the first part after half of the development time that was published in View Camera magazine the very early 1990s. And of course, this is a fairly primitive way of dealing with the problem. A much simpler method is to just add a bit more sulfite to the working solution, as described in the Film Developing Cookbook of Anchell and Troop which was published in 1998. Or you could also add a bit of ascorbic acid, which as the method used by Harald Leban in the Rollo Pyro formula but it work perfectly well with PMK as well.

Course, even if you were not the first to use the method there is nothing to prevent you from claiming that you were. There are many people who believe they are the first to use coating rods to apply emulsions to film, and/or carbon tissue, in spite of the fact that this is well documented in literature from the 1800s.

Sandy