Complex Issue With Scanning and Sizing and DPI (oh my!)

[Rob]

Ok so I'm looking for some sort of solid numbers/consensus on what we need to do here and I'll be as specific as I can but if you don't understand something please ask so things don't get cluttered here with incorrect conclusions.

My new artist is trying to set up a sort of template for creating our comics. He pencils and inks traditionally (he even does his lettering and word balloons traditionally) and then scans the inks in to color and shade the comic.

We have always created our comics at a size of 3000 X 1701. The primary reason for this is because I wanted large versions for our Flash Viewer (if you click on our comics it zooms in to one panel and makes it as large as your monitor will allow) and because a year ago I didn't understand that the DPI was equally important I thought that larger would be better for use with printing down the road.

The images are resized by the flash viewer program which reduces them to 800 X 454 for regular viewing. If you go to Remedial Comics and look at the comics there without activating the flash viewer all the comics will be presented to you at 800 X 454.

Now what we are trying to do is set up a sort of template for him so when he's drawing with his pencil he can be assured that the area he's using to draw is comparable to the size he will need for the final product when he scans it in.

His scanner does not have a scan in range of 350 DPI. There is a 300 DPI setting but I feel from what I've read from a couple printers that 350 would be better so he's been scanning in at 600 DPI.

Now I'll be the first to admit that I don't know diddly about Photoshop. What I do know is self taught. So I've been playing around trying to solve this riddle and I've come up empty. So I'm asking you guys for help.

Here is what I've found so far.

3000 X 1701 at 600 DPI leaves me with a Document size of 5 Inches by 2.835 inches. While the Pixels are right and the DPI is more than we need the document size is tiny for some reason. I don't know why. It's beyond me.

Additionally, changing the DPI from 600 to 350 changes the pixels to 1750 X 992 but leaves the document size at 5 Inches by 2.835 inches. Once again I am left clueless.

However creating a new document that is 3000 X 1701 and setting the DPI at 350 gives me a document size of 8.571 Inches by 4.86 inches. This is better. Still not ideal If I was printing it for a book I'd probably want to go full page with two comics per page and a brief paragraph beneath them like Penny Arcade does for theirs.

But at least at 8.571 by 4.86 inches I'm at least in the ball park. I can reduce the height and width a bit and I'm within the 8.5 inches wide and 11 inches high of a regular sized page.

I think. But it seems like something of a Gordian Knot. Change one thing and you screw up two others. I can say that since pixels don't matter in the printing equation it seems like I'm somewhat "there" with this setup because I can change the document size (make it slightly smaller to fit on the page) without screwing with the DPI and all it does is reduce the pixels which (and Lord I hope I'm right about this) doesn't matter for printing since pixels are a computer thing.

So the real question here is, what document size (actual paper) can he use that will scan in at 600 DPI and translate into a document that is 3000 X 1701 pixels, at 350 DPI and a document size of 8.571 by 4.86?

Or would it be better to just use a document that is slightly larger than 8.571 by 4.86 inches and then trim the excess after scanning it in at 600 DPI?

Hmmm... that might be the way to go. Make the template that is 9 Inches by 5 Inches with a usable area of 8.571 by 4.86 inches and then scan it in at 600 DPI.... then trim the excess off until it is 8.571 by 4.86? Then at that point we should be able to reduce the pixel count to 3000X1701 and then save for the web at which point the computer (photoshop) will change the DPI to 72 without changing the pixel size from 3000X1701 and we'll still have the original at 600 DPI which will also be at 8.571 by 4.86 inches which we can reduce slightly to fit the page size.

Hmm I think that might be the way to go. Can anyone give me any opinions here? Check my math so to speak?

Also, Corey's lines can look a little jaggy and stairsteppy when you zoom in even a little bit. We've tried a couple things to smooth them out. This sizing/scanning thing may help once it's resolved but if any of you have any tips for smoothing traditional inks once scanned t'would be appreciated.

Thanks.  ;D

[ran]

The paper size has nothing to do with how big the scan is coming out. I can put a full sheet of paper into my scanner, scan it at 72dpi, and then scan a playing card and have it come out in larger dimensions than the paper on every scanner I've ever used, which means he either needs to read a manual for his scanner or get some help by specifically googling troubleshooting for his make and model of scanner, and if that doesn't work, he needs to get a new scanner.

[Largento]

Rob, if it were me, I'd approach it differently.

First, I would try to determine what size It's going to be printed at (assuming that's the eventual goal) and then from there find out how much larger your artist would prefer to work. 1 and 1/2 times is pretty normal, but some people like to work even larger.

Let's say you make it 11" x 6" (rather than a size that requires measuring to  100ths of an inch). At 1 & 1/2 times, that would mean the artist would work at 16.5 x 9. I would scan that in at 300 dpi and then reduce it to the final print size (keeping the resolution at 300 dpi.)

This would give you a file with a pixel size of 3300 x 1800, plenty big for your Flash Viewer. Your 72dpi version might be slightly different (792 x 432), but it makes more sense to have  the pixel size be odd than trying to work with odd sized originals.

[Alectric]

The way my scanner works is that it allows you to select the resolution you want the scanned image to be.  This value is given the units "dpi".  If this is the case for your artist, he would choose "600".  It also has a field for Target Size.  For this I would put "Letter (8 1/2 * 11 in.)" so that anything smaller than a regular piece of paper fits in.

Then in Photoshop, rotate the image to get the comic oriented properly.  Then move the comic itself to one corner of the image.  Now go to Image -> Canvas Size, place the anchor in the same corner as the comic, and set the dimesions to 8.571 by 4.86.  This will give you the document size you want.

Now just go to Image -> Image Size, and change the resolution from 600 to 350 (this one is labeled "pixels/inch", but it seems to be the same thing as the scanner resolution).

This should get you what you wanted.  So I guess the answer would be to create the comic at the same size you want the digital document size to be, 8.571 by 4.86.  But then if that's true, then there would only ever be one value for resolution, while you seem to be referring to two.  So I don't know what I'm missing. :-\

[Rob]

I think one of the thing I probably should have mentioned...  :-[

Is that the width of the comic is fixed at 800 pixels for display. The reason being that the width of the comic module created for the website was made to accept that width. The height scales so I can adjust that. In fact the number that I've run leave me with a need for 3 additional pixels in height which I'm told by Chadm1n will work just fine as scaling in height as I said, already part of the system.

But I don't think I can monkey with the width much and that's why I'm stuck with some funky numbers.

However I was ab;e to up it to 8.751 by 5 inches which is really just eight and three quarters inches by five so that gave us something a little more standard as that fits neatly on an 11 by 8.5 piece of paper. However if Corey needs to work bigger we may end up just multiplying by 1.25 so we have a consistent number to work with.

Largento (as long as I've known you I've desperately wanted to sound cool by casually referring to you as Large... are we there yet? Can I pull that off? LOL); the above info was mostly for you. Your plan is a good one but the width requirement somewhat blows it up. There is one other issue though. I don't think Corey has paper as big as you are suggesting and I am also pretty certain that his scanner will not accept paper that big. It's a Dell all in one printer, scanner fax thing.

Also, Ran the printer is brand new but the RTFM is acknowledged and I'll pass it on. My own knowledge of scanners is woefully incomplete so I may be the wrong guy trying to figure this out for him.

Alec I've never heard of the "Target Size" thing you speak of but I'll mention it to him when I talk to him again. Between that and the manual maybe we can figure out something better than my long division.

[Alectric]

I use an Epson printer/scanner, and Target Size seems to be just the portion of the scanning area that you actually want to use to create a scanned image.  The area in my scanner is longer than a sheet of paper, so if I choose Letter Size, it just ignores one or both ends of the scanned image depending on where I put the selection.  I don't know much about it, honestly, or about how other scanners work...

[Knara]

This is rough, because you're requiring a certain height as well as a certain width in pixels, not inches/cms.  Hrm.

When I used to do comics in this sort of hybrid traditional/digital way, I didn't limit the height (it was what it was), just the width.  That made it *much* easier, because I just scanned at the highest practical DPI and then reduced the image size in PS before exporting to jpg/gif/whatever.

You could, perhaps, use a variation on what I used to do.  In photoshop:

New-> CMYK Document @ 800x454@72dpi

Once that's up, go Image->Image Size->600dpi (which will upscale the number of pixels but in the same ratio as your target size -- that is, if you went back in and typed in "72dpi" later, you'll get back to 800x454).

Now in PS make it into whatever sort of template you want (logos, etc).  The trick I used was that the template had a fill layer of white but the frames themselves had "holes" cut into the layer, so that the frames themselves were transparent (this makes no difference at the moment, but is important in a second).

So it was, top layer to bottom layer:
Logos
Black frame borders
White layer with holes cut in it

Save.  Then print it out with "Scale to Fit Media" turned on if its too large for your target page size.  It'll change the overall template size but it will still be in proportion to your target resolution(and the high dpi should keep distortion artifacts to a minimum).

Then, when your artist is done, you scan it back in at as high a DPI as you can.  In Photoshop open up the template document you created, then open the scanned comic in another window.  Arrange both those windows up so you can drag the layer with the comic art from the imported art file window to the template file window.

Arrange the new layer in the template file so that the comic art is "under" the white layer, and then use the transform controls to resize it so that the panel borders line up (it may help to reduce the opacity of the white layer at this step, just remember to turn it back on when you're done).

This worked okay for me because my workflow resulted in the comic and template still being in the same ratio, but the comic being larger, so the resize always made it smaller (but still fit in the frames). 

Then when you're happy, you lock everything down, "Save As.." to whatever your naming convention is (make sure to "Save As..." a .psd), then Image -> Image Size and set it to 72dpi which (because you're using the template you originally made at your target resolution will be *exactly* that original, required resolution).

Finally, do a "Save For Web" to your target file format.

Caveats: With the "holes in white" method you can't do word balloons that overlap the frame borders.  But, on the other hand, you're potentially having issues because non-digital lettering doesn't let you adjust things if the end result is marginally legible.

You *could* do it without the "holes in white" layer, adjust the imported comic art, and then place the logos/etc afterwards.  I think some folks do it that way.  Just always remember that its better to scan at too large a DPI than too small.

Additionally, if your ratio is off with the "holes in white" bit, you will obscure comic art, which, if your dialog is too close to the borders, can be an issue.  Alternately, you could not do the borders and white layer ahead of time, but instead add it in to correspond to the borders as they are in the comic artwork (this way you lose little but still retain the advantage of having the set-ratio template).

If you're like me, you'll also need to play with the scan preferences (keep in mind you can do a TWAIN import from Photoshop itself, as well) so that you end up with artwork quality that isn't a garish contrast from the Photoshop-created elements.

All of this is why I'm 100% digital now  ;D

[Rob]

Wow. Thanks that is very in depth. Much appreciated.  ;)

[klingers]

This is only partly relevant, but I don't think it can hurt to throw it out there. Maybe someone'll get some use out of a little secret someone once taught me years ago.

As a disclaimer I've sort of given up at hand-drawing and inking because I'm erm... rubbish, but it's a fantastic technique.

I can't remember that much about the actual DPI's involved and such but basically I would just scan at a very high resolution in 2-bit black and white colour. That would have the added advantage of cleaning up artifacts on the page, but effectively you're removing all anti-aliasing from your scanned linework until you adjust the image size down.

Next copy-paste that scanned linework into a new image with the same DPI but your appropriate colour depth.  You can color on a separate layer, do bucket fills if that's your thing, whatever, but you won't have to worry about any problems with the fill or colouring having a pixelated mess on the inside of linework.

Obviously if you were scanning to print then you're working with much higher DPI's for your end-product and jaggy lines could still be an issue, but if you just scale up by a factor of two on your print resolution when you scan and then you're fine.

[Shouri]

I'd like to explain a bit the whole DPI issue as I see many people are getting the wrong impression from it. DPI stands for dots per inch. Pretty straightfoward, it tells you that, in a 300 dpi ratio, there will be 300 pixels per inch on the canvas (an 1 inch x 1 inch canvas will have 300x300 pixels). 300dpi is standard for quality printing (mostly, offset, digital offset, etc).

Usually when working on digital files for printing, you will first check with the printer as to what their specifications are, and then make the file. But since we're mainly a web-first format, we need to go with generalizations and hoping that, if in the future we make prints, our files will meet the requirements :) Many people draw at 300dpi, 350dpi, 600dpi, others at 900dpi... This just represents how large your original file will be. Let me tell you, if you send a 900dpi A4 file to a printer, they will ask you to resize it :x Why? Because most of the time, printers (and RIPs) can't handle such large resolutions. In fact, most laser printers will not print upwards 150dpi of resolution (meaning, that a 300dpi A4 file and a 150dpi A4 will have the same look on paper, because the printer will automatically change the resolution to 150dpi to process the file! This is why we need to print proofs beforehand to see how it will turn out).

Ok, back to the main subject. When creating digital originals, always work upwards 300dpi if you plan to print in the future. When you create these digital originals, pixel size has little meaning. You need to keep an eye on cm/inches (depending what you use). This will tell you the real printing output result, NOT the pixel number.

However! Once you have your comic finished and pretty, you need to tweak it so it's good for screen and web. Step #1 is to downsize the quality to 72dpi. Why, if 300pixels at 300dpi are the same as 300pixels at 72dpi? Because of file size. And the same reason why regular printers don't take 900dpi file size, the device is not good to display it! Also, your file is gonna have a lot of metadata saved, and that will make the file very heavy, which will make you waste a lot of bandwidth and downloading time. If you're using Adobe Photoshop, use Save for Web. It will remove a lot of this metadata and your filesize will be at least half of the filesize if you just saved as (I've read that Adobe Fireworks has a more enhanced Save for web, but I haven't tested it yet). Also I should mention that it's good if you keep your originals saved as a lossless file such as .PSD or .TIFF. The way JPEG compression works, is that your pixels will be rearranged each time you save, which people call this "losing information" (more noticeable with photography, but it's important to keep this in mind).

CMYK: print in colors. RGB: web display. Grayscale: if you print in only black ink. This is very important! Sometimes browsers won't display CMYK files so it's important that when you save for web, change it to RGB. Printers will ask you to change your files to CMYK for print, and if you print in black and white, to Grayscale.


Everyone has a different way of doing their art, and that's great. You just need to find the best way to make it work. For Springiette, I make quick sketches on paper of the characters, no layouts. Then I scan those images, and resize and arrange them on my Strip template, then ink on top of that. For my new comic, I plan to either sketch digitally or on paper, then ink on Manga Studio which is sort of a vector hybrid, which means I can export at 600dpi then resize to 300dpi. (I should add, 600dpi is what they use in Manga industry. Because of the way it's printed (one color pass offset, grayscale), the image needs to be clear. In your particular situation, if the inking is done traditionally, I would draw my originals on a piece of paper that will be DOUBLE the size of your printed page (if you want to print at A5, draw in A4, etc). Scan at 300dpi (or 600dpi, depending on your computer/scanner), color. Save originals large. (This way, the original art is large, thus the canvas size will be large, and the printing output will be large. And you'll be able to resize it to whatever size you need! This is much better than just grabbing a small drawing and kicking up the dpi at the moment of scanning. Clearer lines too!) Then copy the file, flatten image, resize to 72dpi and the pixel size you want your page to display on your website. When you are ready to print, grab that file, make sure it's CMYK, resize it to printing size (always keeping in mind bleed lines). Save at whatever resolution and colorspace the printer asks you. Happy files! :)


I hope this helped a bit :X (Just for reference, I am an assistant at university in digital graphic design/printing class. So if you have any questions about printing... I'll be happy to help.)

[Rob]

Shouri, thanks for the detailed analysis.

I think we may have gotten it worked out at least for now with some math and templates. But essentially we are working on a template that defines the entire comic area as 8.751X5 inches. This, scanned in at 600 DPI scales down to 3063 X 1750 pixels for our upload and when further scales down for presentation to 800 X 457 Pixels which is only a three pixel difference in height which our comic module can scale to just fine.

Further it gives us nice big 600 DPI files at a large pixel size and accurate document size for printing later. Depending upon the printer's requirements we can reduce the DPI without losing document size and so on.

All of this is predicated on Corey's ability to create pencil and ink originals within that 8.751 X 5 Inch space. Which, once you make room for borders, add title, comic title, copyright info and define panel borders is actually smaller than the 8.751 X 5 by at least a half inch in height and probably the same in width roughly.

I've told him that if he cannot work within that space we will do the math and upscale the originals to an order of magnitude that will give him more space (something like 1.25 times 8.751 X 5).

The biggest issue with any increase in original size is his scanner. There are limitations on how big a page his scanner can handle. It's a simple Dell all in one Printer/Scanner/Fax thing and if we go beyond the machines ability to scan a document that may leave us with cutting up and digitally reassembling the originals which is not an optimal solution.

So that's where we're at now. If he's ok working in that small space we'll be fine. If not we'll have to do some more math and try and figure out how we can upscale without going beyond what his scanner can handle or make the compromise that we will indeed have to cut up the comics and reassemble them digitally before coloring.