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Many of you have been asking me about Digital Camera images and Photo Resolution.

This is information that is common to ALL Offset Commercial Printers across the globe when dealing with photos whether it is a Calendar or a Business card. I know this resembles a Jim G. post, but I really want the Photos for the SSR Calendar to look as best as they can

A good 4, 5 or 6 Mega Pixel Camera set to the highest pixel setting should shoot a photo that can be used for the calendar. 3 MP and lower and the images will start to blur as the resolution is changed and the image is blown up to size.


Q - Digital Cameras shoot 72 dpi and RGB (Red, Green Blue)....Why?
A - 90% of all the desktop printers out there (Color or laser) print based on 72 DPI. 72 DPI is also the resolution of computer monitors. When computers first hit, you couldn’t save or print larger images, so this “low” resolution was adopted and everything since has been building on it. RGB is the color space for monitors, it was logical to make the desktop printers use RGB ink. (BTW – most need a separate black ink cartridge, because black doesn’t exist in the RGB world)

Q – Why then do Offset Commercial Printers use 300 DPI and CMYK?
A – Printers have been using Cyan, Magenta, Yellow and Black to print for over 100 years. RGB was a technique used for movies (Technicolor) and was adapted to color TV’s. I will spare you the reflective and absorbent color theories....What’s more important is you can create far more color combinations with CMYK than RGB and CMYK looks better on Paper. (I won’t go into spending 7 figures on a press that will run for the next 30 years)

Why 300 dpi? First DPI to you is different than DPI to me. In the Computer world, DPI, LPI, PPI have all evolved into the same thing...Photo resolution. To me, DPI is dots per inch. Photos were a continuous tone process that were “Screened” with DPI. Commercial printers generally used 150 DPI. (look at a magazine with a magnifying glass you will see printing is nothing but color dots.) 150 DPI just means 150 little dots per 1 inch of printing...nothing to do with computers.

When we started using computers in the 80’s, printing photos were the equivalent of today’s 4600 DPI! We needed to find the lowest DPI value that could offset print and still save to the hard drives (or tape drives) of the time. 300 DPI was the value equivalent before photos started to blur or pixelize. Note that we were using computers that cost millions of dollars at the time. It was also noted that a photo that was lower could not be brought back up to 300 DPI because the digital information just wasn’t there. So 300 DPI was adopted as the minimum resolution Standard.

I know it’s confusing, but desktop and offset printing are two different worlds that collide all the time. I have taught classes on this subject and never attempt to fully explain this in one post.....But we are here to inform......


Joe Davis
StepPrinting.com
 

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Good explaination. I'm trying to get people to just simplfy the equation by just using the PPI out of the camera ie: 3000 x 2400 is the same as an 10 x 8 @ 300 DPI. I know it is very confussing to most people. Good Luck
 

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I DO WINDOWS
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gosh darn

I did question this file size thing when we started the photo a month contest, just to avoid this problem. Well maybe a SMALL desktop folder type.
Or everyone take a batch of new shots and have a monster month top 12. Maybe run 6 diff contests at once. Whats the big dogs say?
 

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StepPrinting said:
Many of you have been asking me about Digital Camera images and Photo Resolution.

This is information that is common to ALL Offset Commercial Printers across the globe when dealing with photos whether it is a Calendar or a Business card. I know this resembles a Jim G. post, but I really want the Photos for the SSR Calendar to look as best as they can

A good 4, 5 or 6 Mega Pixel Camera set to the highest pixel setting should shoot a photo that can be used for the calendar. 3 MP and lower and the images will start to blur as the resolution is changed and the image is blown up to size.


Q - Digital Cameras shoot 72 dpi and RGB (Red, Green Blue)....Why?
A - 90% of all the desktop printers out there (Color or laser) print based on 72 DPI. 72 DPI is also the resolution of computer monitors. When computers first hit, you couldn’t save or print larger images, so this “low” resolution was adopted and everything since has been building on it. RGB is the color space for monitors, it was logical to make the desktop printers use RGB ink. (BTW – most need a separate black ink cartridge, because black doesn’t exist in the RGB world)

Q – Why then do Offset Commercial Printers use 300 DPI and CMYK?
A – Printers have been using Cyan, Magenta, Yellow and Black to print for over 100 years. RGB was a technique used for movies (Technicolor) and was adapted to color TV’s. I will spare you the reflective and absorbent color theories....What’s more important is you can create far more color combinations with CMYK than RGB and CMYK looks better on Paper. (I won’t go into spending 7 figures on a press that will run for the next 30 years)

Why 300 dpi? First DPI to you is different than DPI to me. In the Computer world, DPI, LPI, PPI have all evolved into the same thing...Photo resolution. To me, DPI is dots per inch. Photos were a continuous tone process that were “Screened” with DPI. Commercial printers generally used 150 DPI. (look at a magazine with a magnifying glass you will see printing is nothing but color dots.) 150 DPI just means 150 little dots per 1 inch of printing...nothing to do with computers.

When we started using computers in the 80’s, printing photos were the equivalent of today’s 4600 DPI! We needed to find the lowest DPI value that could offset print and still save to the hard drives (or tape drives) of the time. 300 DPI was the value equivalent before photos started to blur or pixelize. Note that we were using computers that cost millions of dollars at the time. It was also noted that a photo that was lower could not be brought back up to 300 DPI because the digital information just wasn’t there. So 300 DPI was adopted as the minimum resolution Standard.

I know it’s confusing, but desktop and offset printing are two different worlds that collide all the time. I have taught classes on this subject and never attempt to fully explain this in one post.....But we are here to inform......


Joe Davis
StepPrinting.com
Thanks for taking the time to explain this. :)
 
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