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DPI (Dots Per Inch)
The images that you are looking at on your monitor are at 72 dpi. Certainly good enough to see the image and tell what you are looking at. But by no stretch of the imagination good enough for reproduction.
When it comes to printing the following holds true. Any image you want printed must be screened. The finer the screen the better the quality of the reproduced image. The screen measurement becomes lines per inch (LPI).
If you were to look at a printed page with a magnifying glass you would see little dots of color in a pattern (rosette). This pattern is achieved in the separations process where a line screen is added to the image so that it can be printed. Any halftone (picture) to be printed must be screened.
LPI now also seems to be also refereed to as DPI in many circles. This type of confusion is another reason you need a professional. To help clear up the confusion and keep you focused on the task at hand.
- 65 - 80 LPI = Newspaper quality screens
- 133 - 150 LPI = Periodical quality screens
- 175 - 200 LPI = High quality catalogue screens
- 250 - 400 LPI = Art reproduction screens
Bits
Every digital image is composed of its smallest element which is called a pixel. The purpose of this image is to illustrate the smallest elements of the image. You can also think of pixels as dots. But not the same kind of dots described in DPI.
Our digital camera is made up of a 4.2 million pixel grid. The new consumer cameras contain upwards of 1 million pixels. The more pixels the better the image's "detail."
Bits (BInary digiT) are the numeric representation of the pixels. The ones and zeros. If you have one bit describing a pixel then it is either zero (black) or one (white). There are no shades of gray. If you have 8 bits you would get 256 combinations of 0's and 1's (shades of gray). Some cameras come as 12 bit devices which offer 4096 shades of gray. Our camera captures 14 bits of data. This will allow you to get 16,384 levels of gray from each pixel that we capture. This is four times the information given by a 12 bit capture.
So far we have talked about shades of gray. Ours is a three shot camera and therefore you will get 42 bits of information (3 X 14). Publishing systems can only handle 24 bits. So why bother with all the additional information?
When you capture more information and use the software that we have you will get much better tonality than if you had simply captured the original 24 bits to start with.
All cameras are not created equally. Some are simply more equal to the task at hand. Always be sure that the tool (camera) and the photographer is up to the job required. Sometimes digital is not the correct solution which is why we offer a broad range of services. As professionals we will always offer our services with your best interests in mind.
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