Scanning vs Photoshop

[rickwinkler]

I'm wondering which way to go when enlarging a print. I shoot 4x5 and scan the slides/negatives into Photoshop. I need to enlarge some shots up to 16x20. My question is in regards to changing the image size in Photoshop. If I scan it in at 4x5 to keep file size down, will I lose quality by enlarging the scanned image or would I be better off scanning it to the needed size?

[Daniel_Buck]

I think you'll most definitely be better off scanning at your print resolution, or higher. I usually scan higher, then downsize after I've made my contrast and other adjustments. Sizing up after your scan won't be as good as having the scan at your native print res, or higher.

[Ron Marshall]

When I print on my Epson I send the image to the printer at 360 pixels per inch.

So for an 11x14 inch print the image size must be at least 11x360= 3960 pixels by 14x360 = 5040.

To get these pixel dimensions from a 4x5 neg I scan at 1200 ppi, which allows me a little crop room, since 3690/4 = 922 and 5040/5 = 1008.

In Photoshop, click on Image size to see the pixel dimensions.

[Anupam]

If I scan it in at 4x5 to keep file size down, will I lose quality by enlarging the scanned image or would I be better off scanning it to the needed size?

I am not sure what this means but it seems like you are confusing pixel size with physical print size. You can scan something at 2000 ppi at 4x5 and then print it at 1000 dpi at 8x10 with the same file - no data lost or added.

[rickwinkler]

when I say I scan it in at 4x5 I mean that the input size is 4x5 at 300 ppi and the output image size is also 4x5. What my question is that once I open that 4x5 image at 300 ppi in Photoshop will I lose quality if I change that 4x5 to 11x14 at 300 ppi? I think what I'm seeing so far is that the answer is yes and I would be better off scanning at a higher resolution. I'm using the Epson V750 Pro and it will scan up to 6400 ppi. Just how high should I actually go with the ppi?

[Ron Marshall]

when I say I scan it in at 4x5 I mean that the input size is 4x5 at 300 ppi and the output image size is also 4x5. What my question is that once I open that 4x5 image at 300 ppi in Photoshop will I lose quality if I change that 4x5 to 11x14 at 300 ppi? I think what I'm seeing so far is that the answer is yes and I would be better off scanning at a higher resolution. I'm using the Epson V750 Pro and it will scan up to 6400 ppi. Just how high should I actually go with the ppi?

A 16x20 is about a 4x enlargement from 4x5 (a bit more since the image area is less than 4x5).

I you want your prints to have 300 ppi then you will have to scan at at least 4x300 =1200. I would scan at 2400 ppi and then downsize before printing.

[Frank Petronio]

You can't ADD any real information by interpolation. It's always better to overscan and crop, adjust, and then scale the image down to the desired size.

If the file size is growing larger when you resize the image for printing, you didn't scan it large enough to begin with.

I don't know what the optimal "real" resolution for your Epson 750 is, but I know it isn't as high as 6400 ppi. It is probably either 2400 or 3200 ppi, do a search and ask that.

When you go really large, like 30 x 40, you end up compromising something -- either ultimate image quality or your wallet -- you'll need professional scans and serious computer RAM and horsepower.

[Daniel_Buck]

if it's like the 4990, it's probably 2400 tops!

[Brian Ellis]

It sounds like you're confusing the dimensions of the file when it's scanned with the size of the print. All that really matters is the size of the file in pixels. Once you have a file of a particular size the size of the print is determined by the number of pixels per inch at which you print. For example, if your file is 1000 pixels on the wide dimension you could make a print 10 inches wide by printing at 100 pixels per inch, 20 inches wide by printing at 50 pixels per inch, 40 inches wide by printing at 25 pixels per inch, etc. (these are obviously not realistic numbers, I use these numbers just to make the math easy and to illustrate the point that file size by itself has nothing to do with the size of the print).

I've always understood that you get the best results by scanning at the largest number of pixels your scanner is capable of resolving, without regard to the size of the print you're planning, and then set the print size in Photoshop. If you don't know that number from published tests (such as those Ted Harris published for various scanners in View Camera magazine a couple years ago) I think it's safe to assume that for prosumer scanners such as the Epson 700/750 the number is about half of the number the manufacturer quotes. If you scan at anything higher than what the scanner is actually capable of resolving you're only creating a bigger file, you aren't gaining anything in terms of resolution in the scan. For my Epson 4990 (and I believe also for the 700/750 series) the tests I've seen indicate that it's capable of resolving about 2100 pixels maximum so that's the size at which I scan.

[Michael Nagl]

I have the same scanner as you, and I made the experience that negatives scanned with the scanner set to 600ppi looked a whole lot grainier than when I scanned with 2400ppi and then downsized the scan in Photoshop. Of course that means you have to handle big files, which can be tiresome, depending on your computer, but it pays.
Setting the scanner to an even higher resolution does not add information but only pixels, since the scanner seems to be optically unable to resolve more than some 1500ppi.

[bernal]

I'm wondering which way to go when enlarging a print. I shoot 4x5 and scan the slides/negatives into Photoshop. I need to enlarge some shots up to 16x20. My question is in regards to changing the image size in Photoshop. If I scan it in at 4x5 to keep file size down, will I lose quality by enlarging the scanned image or would I be better off scanning it to the needed size?


Brian is right. You should scan at the highest resolution your scanner is capable of and create a master file. You can then set the desired output (print) size and image resolution in Photoshop from a copy of the master file at the printing stage. Keep in mind that image resolution and printer resolution are two different things. Image resolution is how pixels visually form and image and printer resolution is how the printer applies the ink to print it. I usually set image resolution at 360 and printer resolution at 1440.

bernal

[Lenny Eiger]

Brian is right. You should scan at the highest resolution your scanner is capable of and create a master file.

I second (third) this. You will lose by interpolating - or at least you won't gain anything.


I usually set image resolution at 360 and printer resolution at 1440.
bernal

I set the size to whatever print size I need and don't resample. This sends whatever I have to the printer. I saw no benefit to downsizing to 360 when I was using an Epson, nor do I now on the Roland dVinci system.

Lenny

[bernal]

I set the size to whatever print size I need and don't resample. This sends whatever I have to the printer. I saw no benefit to downsizing to 360 when I was using an Epson, nor do I now on the Roland dVinci system.

Hi Lenny,
I agree. I don't think there is any visual benefit by downsizing image resolution to 360dpi. But what about file size and printing time? For example, I believe an 8"x10" image at 2000dpi will be larger in file size than and 8"x10" at 360dpi, therefore taking longer to print.

By the way, I visited your website. What a gallery of beautiful images!

bernal

[Kirk Gittings]

I believe an 8"x10" image at 2000dpi will be larger in file size than and 8"x10" at 360dpi, therefore taking longer to print.


The printer driver will downsize the file automatically to its native resolution. This takes a few seconds at most.

[Frank Petronio]

Yeah back in the slow olden days I used to resize to 100% for printing and for Quark, now I just change the dimensions and keep the large file size untouched.

[Brian Ellis]

Lenny Eigner said: "I set the size to whatever print size I need and don't resample. This sends whatever I have to the printer. I saw no benefit to downsizing to 360 when I was using an Epson, nor do I now on the Roland dVinci system."

Glad to hear someone as knowledgeable as you say this. I do the same thing, just set the print size and let the ppi fall where they may. I so often see recommendations to resample to 360 so I tried that for a while. I didn't see one iota of difference between prints made after resampling and prints made at whatever ppi happened to result after setting the print size (normally of course a lot higher than 360 ppi). But I keep seeing the 360 resampling business so I've always wondered if others see something I missed. So it's nice to hear that I'm not alone.

[Michael Chmilar]

If you want to apply sharpening before printing, the parameters for the sharpening operation are specific to the print size. In that case, you want to resize the image to the output resolution, and then perform the sharpening.

[Tyler Boley]

the resampling 360 thing is an anecdotal approach that may have been relevant years ago, but hangs in there...
Throw as much info (real native info) at the printer via driver or RIP as you can. Unless you have some proven resample/sharpen method, like Qimage or others, you have seen for yourself ON PAPER.
I use a RIP, but on the odd occasion I print out of PS, I don't even resize there, I just select my paper size with page setup and size the image in the print preview dialog. The driver does what i needs to do...
Tyler

[Lenny Eiger]

By the way, I visited your website. What a gallery of beautiful images!
bernal

Bernal,

Thanks very much!

Tyler already answered the bit about downsampling and print time, and I agree with him. I think the black box takes everything down to 720, but it's total conjecture on my part - "I think" that's what happens, rather than "I know". I have seen a difference between 360 and 720, but few non-photographers would. I also like to print in b&w a little higher. The b&w inkset is very sensitive and I think it makes a difference.

Lenny

[Tyler Boley]

as an ink worker I have no problem saying there are many that should, in fact, do that. For me, when ink finally started to come together, it was clear it was how my work came alive more than ever, and had the greatest affinity for the process. I was in the darkroom for decades before that, the zone system, the whole deal, including platinum. My prints were dandy, but now I can finally make the prints I really want.
But I actually think more are moving out of the darkroom than should, just changing with the times without enough good reason.
Just more choices, all of these processes can be beautiful in their unique ways.
Tyler

[Lenny Eiger]

Why not buy an enlarger, lens, chemistry & trays and make traditional prints?

Fair question. (And I actually have all that stuff.)

I was a darkroom printer, started in the late 60's. In the late 70's I moved into platinum. I got to use very beautiful papers that other artists and printmakers used. I also saw that the matte surface of these types of papers - that had no shine at all - allowed a particular type of effect to occur. It made things appear much more three-dimensional, and viewers would often report that they "fell into the image". To me, this was a much more participatory form of the art, something I value highly.

My art attempts to be much more about what things feel like vs what they look like. I am not into what I call "shock and awe" or what my father (also a photographer) used to call "impact". I don't want to create high contrast images. It's just my personal preference.

Toward this end, a darkroom print can not compare to either platinum, or the prints I am making now. I have made comparisons and they pale - based on my personal criteria. I am not trying to make the statement that all darkroom prints are "xyz". I am simply saying that for my personal aesthetic, the inkjet prints are far superior.

It would be a lot easier to make darkroom prints, in fact. I'm doing it this way because it gives me the results I want.

Lenny

[mdd99]

I'm doing it this way because it gives me the results I want.

This is all that counts.

[neil poulsen]

. . . I've always understood that you get the best results by scanning at the largest number of pixels your scanner is capable of resolving, without regard to the size of the print you're planning, and then set the print size in Photoshop. . . .

I think that there may be more meaning in Brian's response than might be readily apparent. I try to scan at the scanner's highest native resolution. That is, scanners often claim higher resolutions than they can scan natively by up-sizing from that highest native resolution.

Put another way, the highest native resolution is the highest resolution the scanner can achieve, without up-sizing the image.

If you need to up-size from the native scanning resolution, up-size in Photoshop. It has better algorithms for that purpose.