Image up-rez'ing (scaling, interpolation), dimensions and short run printing

[photosnob]

My system: Windows 7 64bit and Photoshop CS2.

Background: I got 1,000+ cartoon like images to print on a A4 format paper.

The original pictures only have 150dpi so I up scaled some samples by only changing the resolution to 300dpi plus I made some little manual enlarging to make the picture fit in a A4 document.
I will load these pictures in Microsoft Publisher and create brochures like documents so I can use the printer's automatic duplex function and save time.

Since: 1) this is a huge work; 2) I've no experience working at this level with an image editor; I would like to ask, am I doing the right thing??
I read a comment from another thread (cartoon like picture) where a member advised to use Bicubic Smoother instead the Bicubic setting I used on a sample, why this choice?
I already printed a final sample on a A4 sheet on both sides and I think that it looks good enough for a cartoon style kid book even so it'll be for an adult.
The printer's driver offers the choice of auto fit the picture in the preview plus the final print has a nice 5mm white border all around without cutting anything from the original picture.

Could anyone please advice me?

 

[Tom Mann]

Doing a separate up-scaling (aka, up-rez'ing) step in may not produce results all that much better than simply letting your printer driver handle the re-sizing to fill the printed page.

Before you commit to all that extra work in PS, you should do some experiments where you compare the results with and without the PS up-rez'ing step.

Also, if you really want to see how the very best up-rezing around compares to PS's native tool and your printer driver, you should download a free trial version of BenVista's Photo Zoom Pro v.5, and include it in your tests. IMHO, it's the best up-rez'er available these days, even better than Genuine Fractals (aka, OnOne Perfect Resize). Photo Zoom Pro features several quite different algorithms, a couple of which are specifically for up-rez'ing graphics (eg, cartoons).

That being said, my guess is that with starting pixel dimensions around 1221 x 1607, and relatively tolerant readers, you probably will decide on just letting the printer handle the up-rez'ing, but of course, to be sure of this, you really have to do comparative experiments.

Cheers,

Tom

 

[Tom Mann]

PS - Also note that Photo Zoom Pro has a batch processing mode, so that if you do decide you do need the very best quality, getting it won't take up much of your time, just money, LOL. You can set Photo Zoom Pro to chew through a directory of images, come back in a couple of hours, and your up-rez'ed images will be waiting for you.

T

 

[photosnob]

Doing a separate up-scaling (aka, up-rez'ing) step in may not produce results all that much better than simply letting your printer driver handle the re-sizing to fill the printed page.

Before you commit to all that extra work in PS, you should do some experiments where you compare the results with and without the PS up-rez'ing step.

I recorded the action in Photoshop so I can resize a whole folder in one step.

Also, if you really want to see how the very best up-rezing around compares to PS's native tool and your printer driver, you should download a free trial version of PhotoZoom and include it in your tests. IMHO, it's the best up-rez'er available these days, even better than Genuine Fractals (aka, OnOne Perfect Resize). Photo Zoom Pro features several quite different algorithms, a couple of which are specifically for up-rez'ing graphics (eg, cartoons).

I forgot to mention that I tried PhotoZoom and soon after Photoshop lost the ability to Automate --> Batch and save the result, I finally gave up and tried the Scripts --> Image Processor which works so I can load a script and resize a whole folder.

That being said, my guess is that with starting pixel dimensions around 1221 x 1607, and relatively tolerant readers, you probably will decide on just letting the printer handle the up-rez'ing, but of course, to be sure of this, you really have to do comparative experiments.

Cheers,

Tom

Ok then I'll try this option (and waste more ink and paper LOL) and see how it goes, perhaps I must still send the pictures to Publisher and create a brochure like document otherwise I'm not able to automatically duplex printing.
Thanks for help.

PS: I'm using a laser color printer.

 

[MrToM]

Hi photosnob,

I'd like to add to Tom's excellent advice, and to just explain those dialogs for you.

If you take the 'Width' and 'Height' values first this tells you the image dimensions in pixels.
If you then look at the 'Resolution' and divide it into either the width or height it will tell you how physically big the image will print at on the paper.



An A4 piece of paper is 8.268" wide by 11.692" high.

Your original values look fine to me:
@150dpi a 1221 x 1607px image will print out @ 8.14" wide, and 10.713" high.
This WILL fit on a piece of A4.....just!

On the other hand your amended values do not work:
@300dpi a 2550 x 3650px image will print out @ 8.5" wide, and 12.167" high.
This WILL NOT fit on a piece of A4 paper.

In your case, I don't think up-scaling is needed, in fact its generally frowned upon to change the amount of pixels in an image because of the impact it has on quality....up-scaling 'adds' pixels to an image (which have to be 'guessed', ...bicubic, bilinear, etc.) and down-scaling removes pixels from the image resulting in loss of detail.
Its not always avoidable but should be as a priority.

If changing the amount of pixels in an image is dismissed this leaves only two other values that can be changed to get the right output size....the document size itself, or the dpi.

If the document size is OK, which in this case it is....just, then that leaves only one thing....the dpi.

When you say 'The original pictures only have 150dpi' this doesn't really ring true, the dpi is not 'fixed' to an image and can be whatever you want, but of course it needs to be of a value that gives you an output size that will fit the paper in the printer.

So to sum up, look at those three values,(px dimensions, document size and dpi), as being a 'balance' that equates to 100%.
If you change any one of them, one or both of the other two values also have to change to compensate, to keep things 100%.

Its for this reason that increasing the dpi results in a smaller output size, and increasing the output size decreases the dpi.

What you change depends on your output criteria, if you HAVE to print @300dpi then you set the dpi to 300 and adjust the other two.
If you HAVE to have a 6" x 4" output size then set the doc size to 6" and 4" and adjust the other two.
If you don't want to up-scale or down-scale, and btw you don't, then leave the px dims and adjust the other two.

If you've ever done photography its very much the same balancing act as Aperture, Shutter speed and ISO for the correct exposure.....changing any one means compensating with one or both of the other two.

I hope that explains those dialogs a little better.
Try not to up or down scale, (Leave the px dims alone and turn OFF Resample Image), and adjust the other values to fit your requirements.

Regards.
MrTom.

 

[Tom Mann]

There is another issue. Are your cartoons contone (ie, continuous tone) artwork such as one might get from the original artists, or half-tone (ie, scans of pages mass produced by a large volume offset press)?

If it's the latter, there is a good chance you might see Moire patterns if the line screen frequency is near some multiple or sub multiple of the ppi in your image file.

Why don't you post a small crop from one of your images so we have a better idea what you are dealing with.

Also, I hope your comment about wasting another page on an experiment wasn't serious. The cost of a few pages for an experiment is utterly insignificant in comparison to a possibly mucked up run of 1000 pages.

Tom

 

[Tom Mann]

BTW, there is an obvious extension of MrTom's recommendation not to avoid up or down-rez'ing, if at all possible:

One of the worst things one can do with respect to loss of detail when printing an image is to execute several up and/or down-rez operations on the same image.

This often happens inadvertently. For example, one might decide to double the dpi by resampling, and you think the new size fits the page, but then, when you send the data to your page layout program, that software modifies the dpi yet again to take into account gutters, margins, bleed areas, etc. Then, if you are really unlucky, when your page layout program sends this new data to your printer, it may go through the manufacturer's printer driver software which decides on it's own that it needs a slightly different sized non-printable area, and changes the dpi once again by resampling.

Tom

 

[photosnob]

Thanks everyone for help and I do believe that all you guys want to give a true technical explanation regarding my issue.
Above there are two image size screen shots regarding the picture I'm talking about.
You guys say that I'm doing wrong this and that and I believe that, so could you please based on Photoshop image size window tell me what to change to increase the pixel number and have a standard A4 picture?

I read that to have a decent print the picture has to have at least 240 ppi so my intent is to increase the number of pixels.
I think that in my case resampling won't affect too much quality unless we want to zoom 800+ in the picture to find problems.

The original picture is "nearly" standard A4 so it's a bit smaller and this will create a problem because I need to stretch it to fit in the final A4 print.

I've attached the sample from the original picture.

Again, I printed a master sample and in my opinion it looks good but I still need your advices before committing any big mistake.
I digitally stretched the picture in a way that the final print has a white border all around (decided by the printer) but nothing is cut out from the picture.

View attachment 47956

Could Photoshop Elements be more suitable for my job? What if I export to pdf format then I can automatically print duplex or booklet? Can Elements from more than one picture or a folder create a pdf document? Will the document change picture's properties and quality?
I chatted with an Adobe representative and of course has was just clueless, he pretended to explain me printer's settings while diverting the main issue, finally he said that Elements cannot do it!
Thanks to everyone.

 

[MrToM]

The original picture is "nearly" standard A4 so it's a bit smaller and this will create a problem because I need to stretch it to fit in the final A4 print.

As I've said before, and to try to keep things simple, digital images are made up of pixels which have no 'linear' measurement to speak of.

A printer does not use pixels, it does use 'linear' measurement, it knows it has a piece of A4 paper to print on and it knows that A4 paper is a fixed width of 8.268".

For the printer to calculate how 'BIG' an image will be when printed it needs some correlation between the amount of pixels in the image and the amount of space in which it has to print.

That correlation is the DPI.

Your image can be printed at ANY size you require, and is set BY YOU using the DPI.

Changing the amount of pixels in an image is regarded as a no-no and should be avoided whenever possible.
If you need to change the OUTPUT size of an image, ie when its printed, then changing the DPI is prefered as opposed to changing the amount of pixels.

The amount of pixels in the image will determine the maximum size of the print given a certain DPI...
As I explained before your second image shows settings that will NOT work for an A4 piece of paper....the OUTPUT size is bigger than the paper.

PS should give you a warning about this if you tried to print it...something along the lines of 'The image is too large for the printer medium, some cropping will occur, continue?'

To overcome this you would increase the DPI so that the OUTPUT size becomes smaller and so fits the paper.

If you want your image to fit exactly onto A4 paper then adjust the DPI until the size is correct.
A4 is 8.268" wide.
Ignoring borders and gutters and suchlike this means with an image of 1221px wide the DPI would have to be 147.6. (1221 / 8.268)

Now, if this is not enough DPI for you, (as you would like 240+ preferably), then you are going to have to change something.
If you FIX the output size to A4 then the pixel dimensions have to change.
If you FIX the pixel dimensions then the OUTPUT size has to change.

By the sounds of it your only choice IS to upsample the image, despite this not being ideal it does seem to be the only choice you have.

To achieve 300dpi you will need an image of 2480px wide. (300 x 8.268)
This is 2.03 times the original size and just over 4 times the total number of pixels.
When you up-scale, use the 'image size' dialog in PS to change the width to 2480px.
Bicubic is fine but do try others, it can be image dependant as to how to the up-scaled image looks.
The DPI should change to 300 when you change the pixel width.
Keep 'Constrain Proportions' checked.
If you have any styles in your document you will want to scale those too so check that option as well.

With those new settings a value of 300dpi will give you an image exactly A4 in size so if you have any borders you will have to recalculate the pixels dimensions based on your requirements.

Regards.
MrTom.

 

[Tom Mann]

1) I can't respond at length at the moment, but for some reason, the attachment to your last post didn't work and all we get is an invalid link. Please try posting it again.

2) What type of file were you trying to post? Unless it is a JPG or GIF, you'll need to zip it before the forum software will accept it.

3) Please respond to my previous question:
"...Are your cartoons contone (ie, continuous tone) artwork such as one might get from the original artists, or half-tone (ie, scans of pages mass produced by a large volume offset press, ie that are made up of a lot of tiny dots)?..."

4) Exactly what model laser printer are you using? When you go to print a document, do you ever see a dialog box put up by your printer driver asking what size you want the print, or do you only see the print dialog box put up by Photoshop?

5) Finally, you state:
"... I printed a master sample and in my opinion it looks good but I still need your advices before committing any big mistake. I digitally stretched the picture in a way that the final print has a white border all around (decided by the printer) but nothing is cut out from the picture. ..."

In order to give you good advice, I need to know many more details about exactly how you got the image, and what you may have done to it before and after you "digitally stretched" it.

For example, did you scan some half-tone reproduction of the cartoon, or do you have the original artwork. If you scanned some object, exactly what settings did you use? What were the linear dimensions (in inches or cm) of the object you scanned? What dpi did you use in scanning? Did you do anything else to it before you "digitally stretched" it? For example, did you change the dpi or pixel dimensions (with or without resampling) before you "digitally stretched" it? When you "digitally stretched it", I presume you went into transform mode in Photoshop and dragged one corner of the image. Is that correct, or did you do something else to "digitally stretch it"?


TomM

 

[KerryEmery]

Tom - do you have a feel for how this would upsize something in the range of 40Mb - 120Mb in a photographic state? I have some smaller images that are only 4-8Mb that I need to upsize a bit to get up to a 24" x 30+" format for posters and am trying to track the best approach without wasting a ton of paper and ink on an epson 7890. Do you think that BenVista's Photo Zoom Pro v.5 is better for this as well? (vs onOne Perfect Resize) I bought it because I remembered using Genuine Fractals years ago...and was amazed at how well it did with upsizing. Thanks for your input. (i'd start a new thread with this - but wasn't sure how to direct it to you ...)

 

[Tom Mann]

Hello again, Kerry - I've got to run out for a few hours, but I will return later and try to say something useful (LOL). ;-)

Cheers,

Tom M

 

[photosnob]

Hello to everyone and thanks for your patience.
I've been so busy with school and family commitments also some health problems too.

I understand now that it's better to leave the pictures as they are because the printer will do the job, it only leaves 5mm white border all around the printing.
I the mean time I bought a colour laser printer Brother HL-4150 which was on sale because it was being discontinued then I found a UNI printing service which will only charges around AU 0.50 per page.
Now I should keep working with my printer because I already bought it, but what do you guys think, it was more convenient to let the UNI do the job for me?

Thanks in advance.

 

[Tom Mann]

Tom - do you have a feel for how this would upsize something in the range of 40Mb - 120Mb in a photographic state? I have some smaller images that are only 4-8Mb that I need to upsize a bit to get up to a 24" x 30+" format for posters and am trying to track the best approach without wasting a ton of paper and ink on an epson 7890. Do you think that BenVista's Photo Zoom Pro v.5 is better for this as well? (vs onOne Perfect Resize) I bought it because I remembered using Genuine Fractals years ago...and was amazed at how well it did with upsizing. Thanks for your input. (i'd start a new thread with this - but wasn't sure how to direct it to you ...)

KerryEmery - Sorry for the delay in getting back to you, but I've been trying to keep too many balls in the air. Anyway, I think I know what you are asking, but I'm not quite sure, so first, let me ask you a few questions then make a few comments.

1. You gave the sizes of your images in "Mb" (ie, megabits), not "MB" (ie, megabytes), or even better, "Megapixels". Since the first unit would imply very small images, I assume you meant, "MB", ie a typical image size from a 12 to 18-ish megapixel camera. Is that correct?

FYI, when one talks about the size of an image, since images come in different formats (eg, raw, TIF, JPG), and can be compressed by various amounts ranging from zero to factors of 5 or more, by far, the best unit to use to describe the size of an image is the number of pixels, or even the image dimensions in pixels, not the file size.

2. You also gave the intended final file size in Mb, so I'll assume that you are up-rez'ing each image by something like 3x to 4x in number of pixels along each axis. Is that correct?

3. You have a very nice 7890, but unless you have a good, color-managed workflow (including profiling the particular combination of paper and inkset that you intend to use), you could easily waste tons of ink and paper getting the colors to be exactly what you see on your monitor. For example, if you didn't purchase the optional paper spectrometer (spectraproofer, or whatever they call it), you should have your printer/paper/inkset profiled by a 3rd party service before you embark on what sounds like a major printing effort.

4. OK ... down to your real question. BenVista's Photo Zoom vs onOne's Perfect Resize / Genuine Fractals. From the tests that I have done, if your images are photographic in nature, ie, lots of textures that must be preserved, versus graphic art images (eg, out of Illustrator, with sharp edges that must be preserved as well as possible), then these two programs are about neck-and-neck, with maybe a very slight edge going to Perfect Resize.

On the other hand, if the images to be up-rez'ed are of the graphics arts variety, they are both good, but Photo Zoom does a noticeably better job.

I should also comment that I seen some claims by Adobe that they have improved their up-rezing. The last time I did a comparison between PS's native up-rezing and Photo Zoom was about 1.5 years ago, so something might have changed since then.

HTH,

Tom M

 

[Tom Mann]

Hello to everyone and thanks for your patience.
I've been so busy with school and family commitments also some health problems too.

I understand now that it's better to leave the pictures as they are because the printer will do the job, it only leaves 5mm white border all around the printing.
I the mean time I bought a colour laser printer Brother HL-4150 which was on sale because it was being discontinued then I found a UNI printing service which will only charges around AU 0.50 per page.
Now I should keep working with my printer because I already bought it, but what do you guys think, it was more convenient to let the UNI do the job for me?

Thanks in advance.

View attachment 56974

Hi again to you, too, Photosnob! If memory serves, it's been almost a year since we've last chatted, .

Anyway, as I see it, the main issue that you will be facing is that if accurate color and tones are important to you, the Brother is aimed at the business graphics market. This means that it's supposed to deliver bright, but not necessarily super accurate colors. This is supported by noting that its spec sheet ( http://www.brother-usa.com/Printer/ModelDetail/1/HL4150CDN/spec#.VZ13v_mPTu0 ) says absolutely nothing about profiling, color accuracy, etc.

I think that's the model of color laser that my wife's office uses, and I've been pretty impressed with it. Fortunately, cartoons like the one you posted don't require as much color accuracy as high quality photos. Since you now own it, why don't you simply run off a few typical sheets and see if it meets your needs.

Unfortunately, your other possibility, the university printing service is just as much of an unknown as your own printer. If it were me, I would approach them, ask them if they can supply you with color profiles for their printers. I doubt they will even know what you are talking about, but it never hurts to ask. Then I would ask them if they could run off a couple of test prints for you, so that you could do a direct comparison with your own printer, and make the call yourself.

One final comment: if the example page that you just posted is representative of your needs, IMHO, the issue of which up-rez'ing method is best is moot because I don't see any fine detail anywhere in the image. If you use your own printer, just print from PS and use its native tools.

HTH,

Tom M

 

[KerryEmery]

@KerryEmery - Sorry for the delay in getting back to you, but I've been trying to keep too many balls in the air. Anyway, I think I know what you are asking, but I'm not quite sure, so first, let me ask you a few questions then make a few comments.

1. You gave the sizes of your images in "Mb" (ie, megabits), not "MB" (ie, megabytes), or even better, "Megapixels". Since the first unit would imply very small images, I assume you meant, "MB", ie a typical image size from a 12 to 18-ish megapixel camera. Is that correct? Yes - I meant MB. I have older images that are in teh 4-12 range - they need upsizing for a 24" wide format (some are landscape as well) - newer images are in around 37MB per image and don't need too much (if any) upsizing for my purposes.

FYI, when one talks about the size of an image, since images come in different formats (eg, raw, TIF, JPG), and can be compressed by various amounts ranging from zero to factors of 5 or more, by far, the best unit to use to describe the size of an image is the number of pixels, or even the image dimensions in pixels, not the file size. I typically start with Raw format or perhaps Tiff (I like to maintain maximum flexibility) with the aforementioned file sizes.

2. You also gave the intended final file size in Mb, so I'll assume that you are up-rez'ing each image by something like 3x to 4x in number of pixels along each axis. Is that correct? That would be a good starting point.

3. You have a very nice 7890, but unless you have a good, color-managed workflow (including profiling the particular combination of paper and inkset that you intend to use), you could easily waste tons of ink and paper getting the colors to be exactly what you see on your monitor. For example, if you didn't purchase the optional paper spectrometer (spectraproofer, or whatever they call it), you should have your printer/paper/inkset profiled by a 3rd party service before you embark on what sounds like a major printing effort. Yes - I'm discovering this is critical aspect and am looking for a cost effective way to do this. From Retina screen to print is not matching all the time.

4. OK ... down to your real question. BenVista's Photo Zoom vs onOne's Perfect Resize / Genuine Fractals. From the tests that I have done, if your images are photographic in nature, ie, lots of textures that must be preserved, versus graphic art images (eg, out of Illustrator, with sharp edges that must be preserved as well as possible), then these two programs are about neck-and-neck, with maybe a very slight edge going to Perfect Resize.

On the other hand, if the images to be up-rez'ed are of the graphics arts variety, they are both good, but Photo Zoom does a noticeably better job.

I should also comment that I seen some claims by Adobe that they have improved their up-rezing. The last time I did a comparison between PS's native up-rezing and Photo Zoom was about 1.5 years ago, so something might have changed since then. I will keep an eye on this and test it as well - I am primarily photo print oriented, and the only other question I have - is do you have any knowledge of the upsizing ratio issues? I read years ago that one had to be aware of multiples and dividing somewhat exactly to get a good conversion without losing noticeable data. Although I'm suspecting that the programs are now most likely managing that for the user nowadays - as most users are not that tech friendly. I have an IT background (graphics as well somewhat) and know the programmers tend to not think like a user either... it used to be an issue - but I'm not clear if the gap has closed on the assumed knowledge base between the programs and the users for usability purposes. (If all that makes any sense...)

HTH,

Tom M

Thanks for your input! - Kerry

 

[Tom Mann]

Hey Kerry - Just wanted to respond to your last question before I fly the coop ...

You are absolutely right that down-rez'ing by a factor of two ratio ( 1/2, 1/4, 1/8, etc.) used to be a big deal, and the last time I tested this, it now offers only a very slight advantage. As you have observed, the introduction of higher order polynomial resizing (eg, bicubic vs bilinear) and fractal resizing has almost completely eliminated this as an important consideration.

When up-rez'ing, there was a similar advantage in the past, but even less so than when down-rez'ing. The errors introduced by the guesswork involved in filling in all the made-up pixels overwhelmed the slight advantage of every N-th pixel landing on exactly an original pixel location if you up-rez only by factors of two.

Cheers,

Tom M

 

[photosnob]

Hi again to you, too, Photosnob! If memory serves, it's been almost a year since we've last chatted,

Indeed I'm back after a year but I'm still alive!

Anyway, as I see it, the main issue that you will be facing is that if accurate color and tones are important to you, the Brother is aimed at the business graphics market. This means that it's supposed to deliver bright, but not necessarily super accurate colors. This is supported by noting that its spec sheet ( http://www.brother-usa.com/Printer/ModelDetail/1/HL4150CDN/spec#.VZ13v_mPTu0 ) says absolutely nothing about profiling, color accuracy, etc.

I think that's the model of color laser that my wife's office uses, and I've been pretty impressed with it. Fortunately, cartoons like the one you posted don't require as much color accuracy as high quality photos. Since you now own it, why don't you simply run off a few typical sheets and see if it meets your needs.

Yes I understand that this job doesn't require a high perfection result so my printer would just do the job fine.

Unfortunately, your other possibility, the university printing service is just as much of an unknown as your own printer. If it were me, I would approach them, ask them if they can supply you with color profiles for their printers. I doubt they will even know what you are talking about, but it never hurts to ask. Then I would ask them if they could run off a couple of test prints for you, so that you could do a direct comparison with your own printer, and make the call yourself.

That would not be possible as I'm not a student of that Uni also they don't print for the public so I'm already lucky that they will laminate the prints for me at the lowest price I could find all around.

One final comment: if the example page that you just posted is representative of your needs, IMHO, the issue of which up-rez'ing method is best is moot because I don't see any fine detail anywhere in the image. If you use your own printer, just print from PS and use its native tools.

HTH,

Tom M

Then I'll simply load the documents in PS and automate the whole process.

Thanks again for help.