There is much to learn about images, and one consideration is resolution. Many times I have been sent an interesting photo snapped with a cell phone camera that the client thinks will be perfect for their poster or brochure. What they do not realize is that cameras are capable of taking images at different resolutions, or pixel dimensions- the number of pixels per inch.
The default on a cell phone camera is usually lo-res, about 72 pixels per inch (also known as 72dpi- which is dots per inch, but for this discussion, the same idea) because the screen display is small, and lower resolution = smaller files and therefore more photos can be stored. You can usually change that setting, and on newer smart phones the cameras take higher res photos. The higher the resolution, the larger the file is and the more space is will take to store. Understandably, a photograph taken with a camera phone will never be as good as one shot from a (good) camera, but if you like taking photos with your phone, and might ever want a print bigger than a postage stamp, change the settings and consider getting more memory in either the device or an add-on memory card.
Print resolution should be 300 dpi- that is 300 pixels for every inch of photograph. A 4" x 6" photo at 300 dpi is over 6MB. The same 4" x 6" photo at 72dpi is only 365K. It is always easier to go down when resizing images; you don't need 300dpi for a website, but if you'll use the same photo for a brochure, get a hi-res shot and expect your designer to size it down for the web. Images viewed at a distance, such as posters or trade show banners, do not need such high resolution, which is good because they are usually dropped in at many times their original size. In this case the designer can swap size for resolution; that same 4" x 6" (6MB) photo at 300dpi becomes only 100 dpi when enlarged to 12" x 18". (4" x 300dpi= 1200 pixels wide, those 1200 pixels over 12" become 100 dpi.)
So think long term when buying photography, or you may have to buy the same image again at a higher resolution for a new project!
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— Put our knowledge and expertise to work for your business— visit our webpage and then contact Canzani Graphics today! —
To be accurate, 300 dpi for 150 line screen was conventional wisdom 20 years ago. It certainly holds true for cosmetic industry - so that every hair or skin pore is accurately reproduced. On the low end, 100 dpi for the final output size is also acceptable in images with broad areas of color, and less requirement for detail in diagonal lines (think sunrise / sunset pix). 72 dpi @ 8x10" still produces a decent 5x7" 133 l.s. reproduction.
ReplyDeleteThank you for the input! I know parameters have changed, but since this is intended for business owners as a basic intro to design terms and standards, I chose not to go into too much technical detail or delve too deeply into specific areas unless someone asks a specific question.
ReplyDeleteHaving just finished some 7' trade show banners, I steer clients towards larger file sizes that I can reduce rather than having to re-purchase an image. I am delighted to get further clarification on any subject, though, and thank you for your comment!