How to adjust your 72 ppi images for output at 300 ppi
Eureka Printing Company, Inc 106 T Street, Eureka, California 95501
(707) 442-5703, (707) 442-6968 Fax
ekaprint@pacbell.net (DSL line)
www.ekaprint.net
Adjusting Digital Camera Resolution
People often ask “Since all my images from my digital camera come into Photoshop
at 72 ppi, how can I get them up to 300 ppi for output for a printing press?” The
process is actually very simple, you just have to uncheck a simple checkbox, but
understanding why, and what it will do to your image, is more important. Here are
the step-by-step guides:
Step 1:
Open the image taken with your digital camera in Photoshop. To increase the
resolution, you really only have one choice (that will maintain the detail and
sharpness of your image) and that is to lower the physical dimensions of the
image (which raises the resolution). This is why three to six-megapixel (and
above) digital cameras are all the rage. Why so large? So you can lower their
physical dimensions (thereby raising the resolution) and still have a decent size
image for outputting to your printer, or a printing press. The larger the original
image, the larger your final high resolution image will end up being. Threemegapixel
cameras produce larger images than two-megapixel cameras, and therefore
enable you to create a larger high resolution image. How big? Read on.
Step 2:
You adjust the resolution by going under the Image menu and choosing Image
Size (shown below). Unfortunately, you can’t just type 300 in the resolution dialog
box and click OK, or you’d wind up with a very large, very fuzzy, very blurry
image. Instead, before you do anything else in this dialog box, turn off the
Resample Image check box. This enables you to change either the width and
height of the image, or the resolution, without damaging the image in any way. It’s
the see-saw effect—increase the resolution, and the Width and Height decrease
proportionally, and vice versa. If you look at the Image Size dialog box shown
below, the image we imported from the digital camera was 20.444” x 21.333” at
72-ppi resolution
.
Step 3:
Before we adjust the resolution, we need to determine how we are going to output
this image. If we are going to print this on a printing press, we have to ask the
print shop what line screen they’re printing the job. This figure will determine
how much resolution we need. If the print shop told us it would be printing at
150 line screen, we could double that figure (to 300 ppi) for how much resolution
we would really need to print that image. With Resample Image turned off, type
300 in the Resolution field, then look at the Width and Height fields. In the Image
Size dialoge box below, you can see that by increasing the resolution to 300 ppi, it
decreased the size of the image to 6.827” x 5.12”.• Uncheck
Step 4:
When you click OK, you won’t see any change on the screen, but if you are one of
those people who need to see a change to know it worked, just make sure
Photoshop’s Rulers are visible first (Mac: Command-R PC: Control-R) then you
will at least see the measurements change, even if the image doesn’t appear to
have changed. As you can see, the key to increasing resolution is shrinking the
physical dimensions and to turn off Resample Image before adjusting the resolution
.
This tutorial only addresses resolution and not the conversion of RBG images to
CMYK. We ask that you convert your images before you send them for output. If you choose not to, we will do the best we can. Even though monitors always use RGB to display colors, the colors you see on your monitor will more closely match the final printed piece if you are viewing them in the CMYK color space
.
Be aware that computer monitors display colors in RGB that will not make the conversion
to CMYK. These colors are said to be “out of the CMYK color gamut”. What happens
is the RGB to CMYK translator just gets as close as possible to the appearance of the original using the CMYK makeup and that’s as good as it can be. Some RGB colors won’t make the translation very well. Here’s a common example: many programs translate the 100% Blue in RGB into a somewhat purple-looking color in CMYK. We
recommend a CMYK value of 100 C-65 M-0 Y-0 K to get a nice clean blue. Working in
the CMYK color space allows you to select the CMYK recipe, or “screen build”, that
gives you the results you want. Another helpful tool is Pantone’s® Four Color Process
Swatch Book that will give you the screen build of CMYK ink formulas.
(www.pantone.com)
So it’s best to select any colors you use for your design elements using CMYK definitions
instead of RGB. This way, you will have a better idea of how they will appear in your printed piece. If you have questions about the conversions, please give us a call.Adjusting Digital Camera Resolution
Adjusting Digital Camera Resolution
How to adjust your 72 ppi images for output at 300 ppi
Eureka Printing Company, Inc 106 T Street, Eureka, California 95501
(707) 442-5703, (707) 442-6968 Fax
ekaprint@pacbell.net (DSL line)
www.ekaprint.net
People often ask “Since all my images from my digital camera come into Photoshop
at 72 ppi, how can I get them up to 300 ppi for output for a printing press?” The
process is actually very simple, you just have to uncheck a simple checkbox, but
understanding why, and what it will do to your image, is more important. Here are
the step-by-step guides:
Step 1:
Open the image taken with your digital camera in Photoshop. To increase the
resolution, you really only have one choice (that will maintain the detail and
sharpness of your image) and that is to lower the physical dimensions of the
image (which raises the resolution). This is why three to six-megapixel (and
above) digital cameras are all the rage. Why so large? So you can lower their
physical dimensions (thereby raising the resolution) and still have a decent size
image for outputting to your printer, or a printing press. The larger the original
image, the larger your final high resolution image will end up being. Threemegapixel
cameras produce larger images than two-megapixel cameras, and therefore
enable you to create a larger high resolution image. How big? Read on.
Step 2:
You adjust the resolution by going under the Image menu and choosing Image
Size (shown below). Unfortunately, you can’t just type 300 in the resolution dialog
box and click OK, or you’d wind up with a very large, very fuzzy, very blurry
image. Instead, before you do anything else in this dialog box, turn off the
Resample Image check box. This enables you to change either the width and
height of the image, or the resolution, without damaging the image in any way. It’s
the see-saw effect—increase the resolution, and the Width and Height decrease
proportionally, and vice versa. If you look at the Image Size dialog box shown
below, the image we imported from the digital camera was 20.444” x 21.333” at
72-ppi resolution
Step 3:
Before we adjust the resolution, we need to determine how we are going to output
this image. If we are going to print this on a printing press, we have to ask the
print shop what line screen they’re printing the job. This figure will determine
how much resolution we need. If the print shop told us it would be printing at
150 line screen, we could double that figure (to 300 ppi) for how much resolution
we would really need to print that image. With Resample Image turned off, type
300 in the Resolution field, then look at the Width and Height fields. In the Image
Size dialoge box below, you can see that by increasing the resolution to 300 ppi, it
decreased the size of the image to 6.827” x 5.12”.• Uncheck
Step 4:
When you click OK, you won’t see any change on the screen, but if you are one of
those people who need to see a change to know it worked, just make sure
Photoshop’s Rulers are visible first (Mac: Command-R PC: Control-R) then you
will at least see the measurements change, even if the image doesn’t appear to
have changed. As you can see, the key to increasing resolution is shrinking the
physical dimensions and to turn off Resample Image before adjusting the resolution
.
This tutorial only addresses resolution and not the conversion of RBG images to
CMYK. We ask that you convert your images before you send them for output. If you choose not to, we will do the best we can. Even though monitors always use RGB to display colors, the colors you see on your monitor will more closely match the final printed piece if you are viewing them in the CMYK color space
.
Be aware that computer monitors display colors in RGB that will not make the conversion
to CMYK. These colors are said to be “out of the CMYK color gamut”. What happens
is the RGB to CMYK translator just gets as close as possible to the appearance of the original using the CMYK makeup and that’s as good as it can be. Some RGB colors won’t make the translation very well. Here’s a common example: many programs translate the 100% Blue in RGB into a somewhat purple-looking color in CMYK. We
recommend a CMYK value of 100 C-65 M-0 Y-0 K to get a nice clean blue. Working in
the CMYK color space allows you to select the CMYK recipe, or “screen build”, that
gives you the results you want. Another helpful tool is Pantone’s® Four Color Process
Swatch Book that will give you the screen build of CMYK ink formulas.
(www.pantone.com)
So it’s best to select any colors you use for your design elements using CMYK definitions
instead of RGB. This way, you will have a better idea of how they will appear in your printed piece. If you have questions about the conversions, please give us a call.CMYK stands for Cyan, Magenta, Yellow & Black.
It is an image format printers use to make “four color separations” for the purpose of creating“plates” that are used on the printing presses to produce the printed material you have ordered.
Think ink.
RGB stands for Red, Green and Blue.
Step 5:
It is how your monitor makes up all of the colors you see on the screen & how digital cameras capture information.
Think light.
Save your file in TIF format, not JPG. Why? Read on.
JPG is the right format for photo images which must be very small files for web sites
or for email. The JPG file is very small, often compressed by 90%, or to only 1/10 of the
original data size, which is very good when modems are involved. However, this
fantastic compression comes with a high price. JPG uses lossy compression (lossy
meaning “with losses”). Lossy means that some image quality is lost when the JPG
data is compressed and saved, and this quality can never be recovered.
Most other file compression methods are lossless, like TIF, which means “fully recoverable”.
Lossless compression always returns the original data, bit-for-bit identical
without any question about differences (losses). We are used to saving data to a file,
and getting it all back when we open that file. Our Word and Excel documents, our
Quicken data, any data at all, we cannot imagine NOT getting back exactly the original
data. TIF, PNG, GIF, BMP and most other image file formats are lossless too. This
integrity requirement does limit efficiency, limiting compression of photo image data
to only 10% to 40% reduction. But most compression methods have full lossless
recoverability as the first requirement.
JPG files don’t work that way. JPG is an exception. JPG compression is not lossless.
JPG compression is lossy. Lossy means “with losses” to image quality. JPG compression
has very high efficiency (relatively tiny files) because it is intentionally designed
to be lossy, designed to give very small files without the requirement for full recoverability.
JPG modifies the image pixel data (color values) to be more convenient for its
compression method. Detail that doesn’t compress well can be ignored (removed
instead of retained). This allows amazing size reductions, but when we open the file
and expand the remaining data to access it again, it is no longer the same data as
before. This lost data is like lost purity or integrity. It can vary in degree, but it is always
unrecoverable corruption of the data. This makes JPG quite different from all the other
file format choices, and is not recommended for high quality print reproduction
.
There are times and places this compromise is an advantage. Web pages and email
files need to be very small and some uses may not need maximum quality. In some
cases, we are willing to compromise quality for size, and this is the purpose of JPG.
Even worse, more quality is lost every time the JPG file is opened, compressed and
saved again. So even editing a JPG image is a questionable decision. You should instead
just discard the JPG file and start over from your archived lossless TIF master,
and send us that file.
