Normal file size????????

[ignatiusjk]

If I'm going to make a 16x20 size print from my 4x5 neg what is a "normal "file size?

[erie patsellis]

For me, it's around 4" x 5".

However if you're printing digitally, you should ask the lab doing the printing, as printer resolutions vary, with the range of 240 to 400 dpi being most common.

[ic-racer]

If you file your negative carrier out to the size of 3 14/16" by 4 13/16" you should be able to print the rebate without the negative falling out of the carrier. Alternately you could use a glass carrier with no filing.

[Mike Anderson]

Image size or file size?

As mentioned image size for print should be targeted for the specific printer (around 300 ppi), so a 16" x 20" image would be...well you can do the math.

But most file formats are compressed so the file size varies with the image. An image that's 90% clear blue sky will compress much more than a complicated busy detailed image.

So there is no normal file size.

If you're sending it out for printing and don't know the native PPI of the printer I would make the image 300 ppi (4800x6000).

...Mike

[Noah A]

It depends what kind of printer you're using. It's probably best to ask your lab.

For my Epson prints from film scans I never go below 240ppi. I drum-scan my film so for 4x5 resolution is not in short supply. For prints up to 40x50, I generally go with 360ppi.

So a 16x20in. print at 360ppi would be around a 120MB file. It should look great as long as your scanner gave you enough pixels

For scans from 6x7cm. I make the larger prints at 240ppi and they still look great.

[Frank Petronio]

If you're scanning, scan it as large as your scanner and system will reasonably manage. Make a master file, don't oversharpen or do anything too destructive, back this up. Then resize to print as needed, with sharpening and tonal adjustments to fit. Save as a new file, with size and date notation, for future use,

[Barry Kirsten]

If you're scanning, scan it as large as your scanner and system will reasonably manage. Make a master file, don't oversharpen or do anything too destructive, back this up. Then resize to print as needed, with sharpening and tonal adjustments to fit. Save as a new file, with size and date notation, for future use,

This raises an interesting point: I understand that when an image file is resized, a degree of interpolation is involved whereby information in adjacent pixels is sampled and applied to pixels involved in the resize. Some claim that this process involves loss of detail in the resized print, and it is better to set scanning resolution at the time of scanning, taking account of the negative size, the degree of enlargement and the printing resolution.

I previously used the method described by Frank, with good results. However some of my earlier LF negs I've had scanned by a lab were all done according to desired print size, i.e. separate scans were done according to whether I wanted 8x10 or 16x20 prints. I believe this is standard practice.

I guess the pivotal factor relating to final print quality is the degree of enlargement involved. Would I be right in assuming that enlargements of say, 3x or 4x may show no visible difference between the two methods, but larger enlargements of say, 5x or more may show some degradation in prints from resized files?

I'd be interested in peoples' thoughts.

Barry.

[rdenney]

I previously used the method described by Frank, with good results. However some of my earlier LF negs I've had scanned by a lab were all done according to desired print size, i.e. separate scans were done according to whether I wanted 8x10 or 16x20 prints. I believe this is standard practice.

You never really know what size you'll want to print something. Scanning at the maximum capability of the scanning device will give you all there is, and if you need more, you have to find a scanner with more resolution.

But there is a deeper point in Frank's work flow, and that's the difference between correcting and targeting. When you first scan a file, you work at the scanner's best resolution, and make the image look the way you want it to look at that resolution. Sharpening here is done for correction--merely to correct for the smear of pixels caused by the scanner or sensor technology. Also, you correct the color for your calibrated and profiled screen, not for your output devices. You also apply whatever creative process you desire to be included in every display of the print, which I call correcting the image to suit your visualization.

The corrected file, once saved, becomes the base file for future application. You'll only replace it when you need something it doesn't offer, which you can obtain by using a better scanning technology.

If you want to make a print from that file, then copy it, and resize it to the optimum output of the printer. As long as the corrected file and the targeted file are at or above the printer's useful maximum resolution, you'll never see any effects of the resizing. If both are at or above your eye's abilities, then you also won't see any effects. Sharpening and color correction for targeting are designed to make it look good on the output device being targeted.

Example: I scan 4x5 in my Epson flatbed at 2400 pixels/inch. That gives me about 8800x11000 pixels in the file. I correct the color to look correct on my calibrated monitor, adjust image settings (curves, etc.), apply any effects such as dodging and burning, spot the file, and apply just enough sharpening to overcome the mild fuzziness of the scanner at that resolution. That sharpening is done at 100% actual pixels on the screen. It would never be visible if the whole image was shrunk sufficiently to fit on the screen. The resulting corrected file represents all I can get out of my scanner.

Then, if I want to make a 16x20 print, I copy the file, view it in Photoshop using the Epson 3800 profile, adjust the color and image settings to look correct with that profile, and then I resize it (once) to that printer's ideal output. My printer looks very good at 240, but it's at its best at 360. My scan supports over 500. I can resize that to 360, and since both resolutions are beyond anything I can see, any inaccuracies in the interpolation will also be too small to see. After resizing, I sharpen it to look good at that resolution. The resized file that is adjusted to look good on the Epson 3800 becomes my targeted file. An HP printer would prefer 300 rather than 360--the targeted resolution is display device-specific.

Rick "whose workflow avoided many do-overs after separating correcting and targeting steps" Denney

[jim kitchen]

Dear Rick,

My scanning process is very similar, where I acquire an RGB file that becomes a master file without sharpening applied during the original scan, simply because my negatives are 8X10. Did I interpret your comment incorrectly, that you sharpen during a scan? Although my Epson 750 scanner produces a softer image even at the optimum focal point, I am not bothered by this today, and I know that I could acquire a sharper drum scanned image, complete with better shadow detail, but that is outside this discussion...

I do not touch this master file, but copy it, rename it, and make the renamed file my working file, going forward. I implement and apply other processes downstream against the copied working file, but our, et al, final file size thought process, happens to be the same, although my files are set to be output at 720 for each finished print.

jim k

[rdenney]

Dear Rick,

My scanning process is very similar, where I acquire an RGB file that becomes a master file without sharpening applied during the original scan, simply because my negatives are 8X10. Did I interpret your comment incorrectly, that you sharpen during a scan?

No. I do it in Photoshop, where I can tailor the sharpening to just correct for the fuzziness of the scanner sensor and no more. I do this also for digital camera images, where I work from unsharpened RAW files and apply just enough sharpening to correct the effects of the anti-aliasing filter. Again, this is a correction step--just to overcome the obvious effects of the digital capture device, not to adjust its appearance at any particular downstream resolution.

Even if I don't resize the image for a given print, I may sharpen again during targeting just because I see the image with a more sharpened appearance at that size. Also, I sharpen images targeted for smaller-resolution output (including web display) than for bigger prints. That seems contradictory because the effects of the AA filter or the scanner fuzziness disappear during downsampling. But those effects were corrected during my correction stage anyway, and sharpening during targeting is what I do to achieve a certain effect. Smaller prints and web displays seem to me to need a bit more sharpening effect to give the same impression as a larger, more detailed print with less sharpening.

That said, given your output versus mine, any disagreement between my workflow and yours should cause me to reconsider my process more than you.

Rick "who also prints at 720 when the resolution is available" Denney