Retaining Quality when printing digitally

[sarahloyd]

Dear All,
I may well be asking a stupid question whick exposes the depths of my ignorance, but I am quite open about how much I don't know anyway

I am currently scanning my 4x5 transparancies. I've just moved over to the Epson V750 pro from the Epson 4990 (both excellent scanners).

The 4990 will scan at an optical resolution of 4800 DPI while the V750 will reach 6400. This nicely retains all that gorgeous detail and quality we are using large format for in the first place.

The down side of course is that I end up with very large files. Photoshop (CS2) processes the files fine except when I go to print them, when it falls over with the error message, "Failed to print due to an error" - which isn't particularly helpful

I've checked the obvious stuff like ensuring I am not runnning out of RAM or SWAP space. A little Googling suggests that photoshop can't print a documents which has more than 300,000 pixels in any one direction.

If you also scan your LF negatives / transparancies how do you retain the quality and detail at printing - this is probably where I get a chorus of people telling me to get back into a wet darkroom

[gari]

Hi Sarah, what size are you printing and at what DPI is the file saved at?
Gari

[Steve Bell]

Flat bed scanners never acheive their claimed resolution, the pixels will be in the scan, but not the detail. I find with my 4990 there's no if little advantage to scanning above 2400 ppi.

If you are scanning at 6400 ppi, this will give you an image that will print 106" wide at 300 dpi, or 133" at 240 dpi, huge. Unless you need to print this size, I would scan at a lower resolution to suit your final print size, or at a resolution to suit the maximum you may print later. If the scan is larger than your print size, I would resize to the print size at 240 dpi or 300 dpi, whatever suits your printer. Also, assumimg you are scanning in 16 bit, convert the file to 8 bit just prior to sharpening and printing, it will bring the file down to a realistic size. It should then print.

None of my images have anything like 300,000 pixels in any one direction, so I've never had need to google it as you have. I doubt this is your problem though, as 5 x 6400 is only 32,000 pixels, well in.

[masch]

Sarah,

I tend to concur with Steve's comments. The general consensus seems to be that "consumer" flatbed scanners tend to optically top out at around 2400 or a little more. There are a number of better flatbeds around, which go a littlehigher (Microtek, etc.) OTOH, most good grade flatbeds tend to gain mainly in the dynamic range.

Scanning at higher resolution will ont draw more data out of the miage, it may however look more pleasing to the eye, rather than upsizing on PS later...

If you want to try printing larger files, have a look at QImage. ( http://www.ddisoftware.com/qimage/ ). I have used it a few times when PS was giving me problems, and it is great for batch printing. Plenty of other options as well. It's about $50, but has a 30 day trial, which is plenty to test it....

Marc

[Joanna Carter]

Sarah, scanning at such high resolutions really is not necessary unless you are going to print large prints like those I did for my exhibition at 40"x32". Even then, 3200dpi was more than adequate, especially when printed with a LightJet printer on to photographic paper.

Don't forget that above 3200dpi, you start to be limited by the grain on the film anyway, so only use high resolutions for images you are going to crop heavily.

As others have said, the guideline is to scan at a resolution that will give you the desired print size at 300 or 240dpi.

[sarahloyd]

Thanks Folks for all the replies, very helpful. To clarify, I have been (until reading your replies) - scanning at the max optical resolution I thought the scanner could handle, so that I had maximum flexibility for cropping at print time. I tend to scan at 48 bit, sharpen last thing, then drop to 16 bit for printing.

I usually print up to 24" width with whatever length keeps the print in proportion (I use a HP130nr) for my LF stuff. I will try all of your suggestions and see what works best.

Thanks again to all! I look forward to meeting some of you folk in the future.



Regards to all
Sarah

[Joanna Carter]

Sarah

May I ask why you would want to reduce the bit depth for printing ? This will tend to reduce the tonal range available for the print driver.

May I recommend the following workflow :

Scan the transparency at 48bit and 2400dpi for 24", 1200dpi for A3, 600dpi for A4 print sizes.

If you have a scanner profile for the type of film used, you should have scanned with no profile in the scanner options and then assign the profile to the image in PS.

I use the ProPhoto profile as this gives a much better colour gamut and when you convert the image from the scanned profile to the ProPhoto profile, you should see a much brighter and fuller detailed image.

If you look at the PS image sizing dialog, you will see that the image is still roughly 5"x4" at the scanning resolution. You need to change the resolution to either 300 or 240dpi but uncheck the resampling button as this can degrade the image.

After I have finished editing, if I need to resize, I have two options : using PS resizing, I sharpen after sizing, but using Genuine Fractals, I sharpen before sizing as this seems to give a better result.

You should now have an image that possesses an untouched background layer and a few adjustment layers, and that is sized to the desired printing size at either 300 or 240dpi.

Take this image and, after ensuring that it has been saved in its full bit depth and with the ProPhoto profile, you should then be able to print without any problem, not forgetting to use the correct profile for the chosen paper and ink in the printer options dialog.

[sarahloyd]

Hi Joanna, I didn't think it was possible to print at 48 bit from Photoshop? Again I am probably revealing my deep ignorance

I also didn't know that printers can take 48bit images at the moment

I have a lot of learning to do here, in addition to using the LF effectively.
Its funny, when I was 15 I thought I knew everything, now the more I find out the more I realise how little I know about anything. Thankfully friendly groups like this exist

Do you find "Genuine Fractals" gives a better result than bicubic on photoshop, the photographic press seems to be ambiguous on this?

I colour manage all the way through my LF workflow calibrating screen, monitor and printer (for my media/ink combinations) and am reasonably confident that what I capture ends up on paper within the technical limits of my equipment (at least as far as colour management goes).

I use a working space of Adobe RGB and I find that "softproofing" with the correct profile for the printer/media combination gives an excellent impression of how the final result will appear.

Do you know how beneficial it is (if at all) to send a resolution higher than 300dpi to printers that state they can handle it or would I be wasting my time?

Regards to all
Sarah

[Joanna Carter]

Hi Joanna, I didn't think it was possible to print at 48 bit from Photoshop? Again I am probably revealing my deep ignorance

All I can tell you is that I have never found it necessary to change the bit depth of an image for printing purposes.

I have a lot of learning to do here

Well, you're certainly not on your own !! That's one of the great things about this group.

Do you find "Genuine Fractals" gives a better result than bicubic on photoshop, the photographic press seems to be ambiguous on this?

At small size increments, I don't think it makes too much difference but if you want to do something drastic, then GF seems to make things easier. Most opinions seem to say that PS resizing should be done in small steps to avoid artefacts but GF seems to be able to cope with fairly big resizing in a single step.

I colour manage all the way through my LF workflow calibrating screen, monitor and printer (for my media/ink combinations) and am reasonably confident that what I capture ends up on paper within the technical limits of my equipment (at least as far as colour management goes).

If you haven't profiled your scanner for the specific film that you are scanning, you will not yet appreciate how much difference this can make. After all, if you don't get the correct colours out of the tranny, you are not going to get the best results out of the rest of the process.

I use a working space of Adobe RGB

Adobe RGB is a very limited gamut colour space; it is intended mainly for web page rendition, not high quality manipulation and printing. If you don't use a scanner profile, how do you get a reasonable colour to start with ? My guess is that you are using the "automatic" adjustments provided on the scanner driver.

May I suggest you try converting one of your images to ProPhoto just to see the extra gamut that you should get ?

and I find that "softproofing" with the correct profile for the printer/media combination gives an excellent impression of how the final result will appear.

You certainly should have a good match between the screen and the print, but unless you profile the scanner, you may find differences between the tranny and both the screen and printer.

Do you know how beneficial it is (if at all) to send a resolution higher than 300dpi to printers that state they can handle it or would I be wasting my time?

I used to think that you should print at 28800 or 57600 because this should give a better image quality, but the truth is that it seems to make absolutely no difference at all, even down to 240dpi, which is the default resolution that PS uses nowadays.

I am hoping to get the V700 scanner; what made you go for the V750 rather than the V700 ? I would be interested to see if you think it is worth the extra.

[sarahloyd]

Thanks Joanna, from your reply lots more reading and investigating for me

I profile the scanner using "EZcolour" a profiling system supplied with the V750pro which establishes profiles using standard icc test images for reflective and transparent media. I profile my monitors using a spyder pro 2 and printers using "print fix" a device with a dedicated scanner that samples known standard test files produced by the printer and produces a profile based on the result.

I thought Adobe RGB was wider than sRGB which is why I adopted it, oh dear, even more reading for me

I went for the V750pro for a number of reasons 1) it had a number of good reviews in the pro press with particular comments made around the "benefit" of the non reflective glass used in the platter. 2) The pro version comes with the full version of Silverfast AI rather than the cut down verson supplied with the v700. 3) Early reviews suggested it was going to be supplied with a liquid mounting system which I am interested in (thats false though - at least mine wasn't).

Having said all the above, comparing the results from my Epson 4990 using Silverfast AI against the V50pro using the same software, I would have been better to have saved my money and stayed with the 4990 for the time being.

Thats not to say the V750pro is a bad scanner, its not its excellent, but so is the 4990 for Large Format. The only place the v750 really shines above the 4990 is for 35mm and if I wanted to do that I would be better with a dedicated 35mm scanner anyway.

For me the price difference isn't justified. I think for LF people would be better sticking with a 4990 and investing in Silverfast AI (as its streets ahead of the supplied Epson Scan, and much better than the cut down version of Silverfast that comes as standard).

The film holders for Medium Format and Large Format supplied with the v700/750 are much more substantial than those supplied with the 4990 but still not brilliant although you can fine tune image focus by adjusting height above the platter.

Thanks again for your kind help
Best Regards to all
Sarah

[masch]

1) it had a number of good reviews in the pro press with particular comments made around the "benefit" of the non reflective glass used in the platter. 2) The pro version comes with the full version of Silverfast AI rather than the cut down verson supplied with the v700.

Sarah,

the NR glass should be making a difference when scanning shadow areas. Normal glass looses about 2-5% per reflective surface (two surfaces per sheet). NR coating usually drops this to about 0.5% or so, depending on wavelength. As such, you should get a increase in real (not theoretical) Dmax of about 5-9% or so.... For scanning transparencies this should be quite useful.

I can't judge the Siverfast pricing though, as I have neer used is as such.

Marc

[masch]

the NR glass should be making a difference when scanning shadow areas. Marc

Sarah,

sorry, it was quite late last night when I wrote this (or I was drunk or both).

The NR coating will not significantly increase Shadow detail. It will however, improve contrast and "colour fidelity" of the scanning process (not beyond what is on the slide though...), which may reduce the amount of colour correction you will need to employ afterwards. A minor Dmax increase should be happening still.

Sorry for my mixup here.


Marc