Sharpening for big prints(30x40)

[Adam Kavalunas]

Hello all,

I've had a couple of differing viewpoints on this subject. Both came from well known photographers and both print at Reed in Denver. One said that photoshop USM is totally inadequate, saying that the sharpening that one sees on the monitor doesnt match the print, the other saying that USM matches exactly with the print. Both do lightjets and both shoot 4x5 color trannies. I as well shoot 4x5, mostly velvia, southwestern landscapes. I have yet to print anything big. Should i consider an alternative sharpening program like NIK?

Adam

[Doug Dolde]

I really like Photokit Sharpener. It has output sharpeners for various printing methods (inkjet, lightjet, etc) at various resolutions. Best to look at the file on screen by going to actual pixels then zoom out one time.

http://www.pixelgenius.com/sharpener/info.html

[Brian Ellis]

In my experience you need to view actual pixels to judge sharpening on the monitor using USM in Photoshop and then it takes a little experience. When I simply size a photograph to say 8x10 and view it at that size on the monitor, then print, the degree of sharpening on the print is almost always greater than it appeared to be on the monitor. But if you use View > Actual Pixels you can get a much better idea of what's really going on.

I find USM in Photoshop to be all I need for sharpening. I've tried a couple of the programs, Fred Miranda's and PK Sharpen (I think that's what it's called) and didn't find any big advantage to using them. However, I don't just set the sharpening parameters in USM and hit "enter." I usually select different areas of the print for different degrees of sharpening (sometimes just two areas, e.g. no sharpening of the sky or water, sharpen everything else the same, or maybe three areas, sky, background, and foreground or in a portrait maybe eyebrows and lashes, skin, clothes). Working that way is a little time-consuming but that's not a problem for me because I work on one print at a time and usually spend a lot of time on that print. But it wouldn't be practical if you were trying to crank out a bunch of prints quickly, in that case one of the sharpening programs might be better than USM in Photoshop (or maybe one of them is better in any case and I just didn't use the ones I tried properly).

[PViapiano]

Using masks for sharpening in PS is a great way to selectively sharpen without accentuating grain in a film scan. By varying the opacity and flow of the paintbrush you have enormous control over the entire process. CS2's Smart Sharpen is worth experimenting with as well...

[Bruce Watson]

One said that photoshop USM is totally inadequate, saying that the sharpening that one sees on the monitor doesnt match the print, the other saying that USM matches exactly with the print.

Much depends on the scan itself. Typically, a consumer flatbed CCD scan needs more sharpening than a professional flatbed CCD, which needs more than a drum scan.

Also, it's very difficult to translate what you see on the monitor to a print. There are a handful of reasons. One is that one is a transmission source, and one is a reflective source. One is that the pixel pitch on the monitor is typically considerably bigger then the pixel pitch on a print - and that pixel in the print is itself made up of a number of ink dots. Because of this looking at 100% pixels in Photoshop is often a 5x enlargement all by itself, so of course it doesn't look like the print.

If you want to optimize your prints, the only way to judge is to make prints. Or at least, print sections out of what would be full sized prints. Change your sharpening parameters from print to print and see what the changes look like on actual prints. Go from there.

[Jack Flesher]

The bottom line is that when you get that large, there is no single tool or one formula that is going to work for optimal sharpening. Brian got it closest when he said view at actual pixel resolution and make adjustments from experience.

Cheers,

[Ron Marshall]

I have adopted the approach that Bruce uses because I found that what looked good on the screen often didn't on the print.

Try printing an 8x10 section of your 30x40 print, with different amounts of USM applied. You will quickly zero in on the required amount.

[David_Senesac]

The main issue is a computer monitor pixel pitch is about 3 times that of the Lightjet printer. Accordingly we set our Windows display screen sizes to be somewhat less than whatever that is. For a 21 inch monitor with typical RGB phosphor dot pitches that will accomodate the 1200x1600 screen size. Thus if one views on a monitor at the same size as the image, Photoshop downsizes the image by one-third thus losing some resolution in the process. If one views the image at actual pixel size, then one Windows display pixel is allocated to each image pixel. However the image size will apear three times as large. Although more detail would be displayed, the perceived resolution is always less sharpness. On images I market on my homepage, besides displaying the usual downsized full image I also provide a small 300x300 pixel crop from appropriate sections of each image, downsized by that one-third, which will display at the same size as the actual print. Thus it gives a better indication of the detail in an image. However the actual print will always appear sharper at that same size as it uses three times as many bits of information.

As for a sharpening program for print files, I've never unsharp mask'd my files globaly. What I do for each image depends on the nature of the image. For images with sky, I will always carefully select the sky, saving it as an alpha channel and may do the same with other frame elements like water and shadows that are best not sharpened at all. Thus will just sharpen what is left while viewed at actual pixel size. I don't like the look of oversharpened images though I see others doing so frequently as a Lightjet print will readily make grainy artifacts that are readily obvious to me regardless whether customers would notice. If I've captured the image well, the resulting big 30x37.5 inch print is going to be impressively sharp without needing to resort to trick like one tends to need to do with smaller formats. ...David

[Brent McSharry]

Thus if one views on a monitor at the same size as the image, Photoshop downsizes the image by one-third thus losing some resolution in the process. If one views the image at actual pixel size, then one Windows display pixel is allocated to each image pixel. However the image size will apear three times as large.

David, like adam, and many others, i strugle with the transition from screen to print. Reading your post it dawned on me that i could actually stand right back with the image set at actual pixels, the distance could easily be worked out depending on the size and resolution of the final print, so that the pixel pitch of the monitor approximated that of the printer. Using a cordless mouse I could scroll around the image from a distance, just to give a final kind of overview before sending the file off to be printed.

Not perfect I know, but worth a go.

[Frank Petronio]

You do realize that you can still make test strips digitally? Try various sharpening amounts on smaller sections to find the idea for your printer.

I like using the CS2 Smart Sharpening with a layer mask that I paint to lessen the amount of sharpening in delicate areas.