Tips and Tricks

SOLUTION TO LOW RESOLUTION

When adding photos to the pages in Booksmart, a popup tell me that the resolution of this image is to low.  All my hundreds of photographs are lower than 7" X 7"  =  2063px  X  2067px.  Does this mean I cant use these photos.

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Posted by
hilka
Oct 1, 2007 2:43pm PDT
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hilka
 

I figured out the above. 

Posted by
hilka
Oct 1, 2007 3:09pm PDT
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hilka
 

what did you figure out? i have the same problem – except i am creating an 8×10 portrait cookbook - and have NOT figured it out. my pics are all in picasa @ 72dpi, much too low a resolution for the large photo "containers" in the blurb layouts. PLEASE HELP!

Posted by
supershannon
Oct 5, 2007 11:57am PDT
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supershannon
 

Photos need to be at least 300dpi for your book.  72dpi is perfect for websites, but for a good quality reproduction in the book, 300dpi is perfect.

Posted by
rudyfan
Oct 5, 2007 12:40pm PDT
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rudyfan
 

72 dpi is the most misleading "standard" in history as it is horribly out of date w/o the hardware and software we use today

 the 72 dpi number is irrevelant 

what really matters is the pixel dimensions of your images 

find out the pixel dimensions of your images, and divide by 300dpi to find out the optimum size you will be able to print them at .

for an image 900×1200 pixels, the max size you could print at before image quality may start to suffer due to resampling, is 3" x 4" (900 px/300 dpi, 1200px/300 dpi)

if your images are smaller than what you’d like to print at you will have to determine how much quality you will be willing  to sacrifice.

but please throw out the antiquitated notions of 72 dpii
a computer display’s relative "ppi" completely depends on the screen size and resolution you are running at. A 600 pixel wide image will measure 9" across in physical space on my 15" widescreen laptop display running at 800×600. But running my display at 1280×854, that same image will only take up 6.37" on my monitor. On my PC’s 17" monitor running at 1600×1200 that image will be another size yet again.

And that same image printed in a blurb book w/o any resizing in the container will measure 2" across on the printed page.

You coul of course size up that image to print so that it is 4" across but then a fully 75% of your image would consist of interpolated pixels, usually enlarging any compression artifacts your original image may have. 

Posted by
brokendreams
Oct 6, 2007 7:58am PDT
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brokendreams
 

that helps some… but basically means that my existing photos can only be reproduced in the smallest "containers" in the blurb layouts. right?

are the pixels determind by the original photo or by the way they were saved when i scanned them??

is there no way to re-save them at a more optimal pixel setting?

...even if i have to re-scan each and every one, it would be worth it to be able to enlarge them in my book!

Posted by
supershannon
Oct 7, 2007 8:57am PDT
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supershannon
 

I don’t know where the previous poster got that 72 dpi doesn’t matter. That is false. I can have a 3000×3000 jpeg at 72 DPI that will be less than a third the size of a 3000×3000 jpeg at 300dpi. the diffrence? the more DPI (Dots per Inch) in the image the more detail. That is the simple breakdown. Yes you can rescan your images at 300 DPI and you will find that they will be more than sufficent to use in your blurb book.

Posted by
jdhane
Oct 10, 2007 2:50pm PDT
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jdhane
 

I don’t get it…  If an image is say 3000 pixels by 3000 pixles where are you getting more data in the image when going from 72dpi to 300dpi.  The image still has only 3000 pixels by 3000 pixels.  (Or am I missing something?)

I have a bunch of tiff images that ares stored at 240 dpi. (According to the image.)  They are around 4368×2912 pixels. (Width and Height)  They are each about 36mb a piece.  I assume these have enought dpi resolution for a good size book.

 So how would changing the dpi have an effect on my width and height?  I can’t add more pixels to the image.  That data is no longer around.  I only have the widht and heigh in pixels in the image.

 Just trying to wrap my head around this.

thanks

 corban

Posted by
corban
Oct 11, 2007 12:02am PDT
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corban
 

[hmm, i ‘ll have to break this post up. blurb tells me: "Not so fast, Tiger. You need to use at least 5 characters to make a post." lol]

 

Until you output an image to a hardcopy device (like a printer), the DPI is an irrelevant number. Nothing more than a tag in the file header that tells you what DPI is associated w/ the image file.

 A 3000×3000 image is going to contain 9,000,000 pixels of resolution detail, no more, no less, no matter what DPI is associated with the image.

Once you want print to your with home color printer, in a program like photoshop, then your DPI setting will matter. At 300 DPI, your printer will pack 300 pixels of your image data into 1 inch on paper. At 72 DPI, 72 pixels in 1 inch will print on your paper. Some simple math will get you your final printed image dimensions – 3000 pixels / 300 dpi = 10 inches or 3000/72 = 41 2/3 inches respectively.

But note that this is completely independent of your output device’s DPI capability. My epson printer claims to print color at 720 DPI and 1440 DPI horizontally (on their top quality paper only of course  <sup>_</sup> ). So if you could actually see the 720 discrete little inkjet ink dots in a row on the print out, you would see that every 2 or 3 dots would be the same color – assuming there’s no dithering or interpolation going on in order to better approximate what you see on the screen. 

In essence your 300 pixels per inch would be mapped to the 720 dots per inch of your printer. Printing your 300 dpi image at 1440 dpi could be overkill given that you’re not going to see things in your printed image that were not in the original photo just because of a higher output dpi. Your image may look smoother because of the finer ink dots, if you’re using the right paper. 

Printing a 72 DPI image on a 720 DPI printer, each pixel from your image will be represented by 10 ink "dots" from your printer. ( Depending on your printer driver, the printer may do quite a bit of "smoothing" with noise and dithering to create the illusion of gradation if you print at a really low dpi. )

Anyway, the same concepts apply to scanning in images into the digital world. Do a little math and you’ll find that scanning a 6×4" photograph at 300 DPI on your flatbed scanner and you should be able to obtain a 1800×1200 pixel image (300dpi x 6", 300dpi x 4"). Is this high enough resolution? Depends on what you are doing with it. If your final output is for the web, this may be just a little large for flickr.. but if you’re printing the image back out at 300 dpi or less it could be just right. 

But I have a lot of old images from my parents’ childhood and those black and whites often measure 1.5" x 2". If I scan them in at 300 dpi that only gives me 450×500 px of resolution. Not good enough if I’d like to print them back out larger at 300 dpi. If I know my output device is 300 DPI, and I want my final photo to measure 6 inches across in the print, ideally I would like my ditigal image to contain 1800×2400 pixels of resolution (6" x 300dpi, 8" x 300dpi). That would mean scanning in the source image of 1.5"x2" at 1200 DPI ( 1800px/1.5", 2400px/2" ).

Not all consumer level scanners can handle that resolution, and for 1200 DPI many scanners may interpolate the incoming data from a lower optical DPI (often 600 DPI optically).  Also be aware that your source material may not hold up to that resolution. For example, if you try to scan an art or photo book at 720 DPI and higher you will begin to see the individual halftone dots.

Also large physical images scanned at high DPI will create files that can be large and unwieldy without gaining you very much in the end.

 So the input DPI at which you scan should always be determined by the size of the original and what you intend to do with the final digital file. Some simple math and you should have a good idea of the resolution you’ll need to scan at. 

  

Posted by
brokendreams
Oct 11, 2007 12:44am PDT
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brokendreams
 

For the blurb pipeline, their software is still part of the digital process, and booksmart couldn’t care less about what the DPI of your image is. All that matters is the "container size" and the "pixel dimensions" of your image. Blurb books will be output at the equivalent of 300 DPI and that will be controlled on their end. All we as the book makers have to be concerned about is whether there is enough pixel resolution in our images to hold up at 300 DPI. Blurb simplifies this for most users by showing the ideal and maximum absolute pixel dimensions of where the image will go.

DPI is a number that is only used when "interfacing" with the digital world and the real world (scanning and printing). And that is why DPI is completely doesn’t matter in the pipe from our computers -> booksmart. All you really need to know is that pixel dimensions of your image and whether or not it is ideal, sufficient or " i can live with that" under given blurb’s output parameters. 

And that’s a good thing too. Just imagine the chaos is blurb actually printed the books using the embedded DPI info in the jpgs. Most digital cameras by default tags their jpg files as 72 DPI

It’s the same reason why most image viewers, email programs and web browsers will give you the option to "fit to page" when printing out an image. Using the 72 DPI default in most images could waste plenty of ink and paper from your home printer before you finally killed the print job.  

 

Where did the 72 DPI number come from? That harks back to the old days of the first Apple computers with WYSIWYG screens in which one inch of screen actually contained about 72 pixels of information. Now we’re stuck with this silly and irrevelant number. Do note that Windows defaults to assuming a display of 96 DPI, and I believe Mac OSX only recently has adopted an assumption of 96 DPI as well. 

 

hope this information is useful with out being overwhelming!  =) 

 

Posted by
brokendreams
Oct 11, 2007 12:45am PDT
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brokendreams
 

hey corban – you’re not missing anything. The simple answer is, there is no difference between 72 and 300 dpi as long as you are in the digital realm. 3000×3000 pixels is 3000×3000 pixels.

Just ignore the DPI embedded in your files.

All you need are the absolute pixel dimensions.

Your 4368×2912 pixel images, when printed at 300 DPI will occupy 14.56×9.71 inches on the printed page. That may be just right, or larger than your needs. You can either let blurb rescale the image (not sure at which point this happens) by resizing the images to fit a container, resize the image yourself before importing into booksmart, or crop the photo if desired since you have plenty of pixels to work with. 

 

The only time it may be useful to set your DPI in a program like photoshop is if you are using the rulers and would like to see how many inches/cm your image is going to occupy without having to do the math yourself. Make sure "resample image" is turned off when setting the DPI though. 

Posted by
brokendreams
Oct 11, 2007 12:59am PDT
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brokendreams
 

correction (just love this forum’s inablitiy to edit posts):

‘But I have a lot of old images from my parents’ childhood and those black and whites often measure 1.5" x 2". If I scan them in at 300 dpi that only gives me 450×500 px of resolution.’

should read: 

 

‘But I have a lot of old images from my parents’ childhood and those black and whites often measure 1.5" x 2". If I scan them in at 300 dpi that only gives me 450×600 px of resolution.’

(300 dpi x 1.5 in   and   300 dpi x 2 in)

 pardon the typos (when is should be if, that should be the, etc, etc) 

Posted by
brokendreams
Oct 11, 2007 1:06am PDT
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brokendreams
 

Hey Brokendreams,

Thank you for your posts!  While yes it was a lot of info, this really helped clear it up.  This now makes way more sense than it did yesterday.

Thank you, this was great!

cheers

corb 

Posted by
corban
Oct 12, 2007 5:38pm PDT
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corban