Note: Kirk is "the Affordable Full time Professional Wedding Photographer Winsdor, Ontario". Here is the Link to KW Masters Photography.
Introduction:
You have heard me talk about the image resolution of the sensor. Today we will look a little closer at this and what it might mean. I will also show you how to increase it to what ever value you would like.
Image Resolution
Strictly speaking, image resolution refers to the MP rating of your camera. I remember when digital camera hit the 1 MP mark. I went Wow! When they hit the 6 MP mark a lot of professional photographers stated that digital now equals the resolution of film cameras.
If you want the best image quality that you can get, then you must shoot at the camera's lowest noise level. This occurs at around the 100 ISO (80 as tested) level as does all of the other key elements to a photo like dynamic range, color, etc.
Printed Images and Resolution
When we look at a computer screen image, the image is normally set at about 100 dpi (dots per inch). It may be as low as 72 dpi. Most silver halide prints are around the 300 dpi mark. So when we look at a print, we are looking at a lot of dots. Larger prints may go as low as 22o dpi. My Epson Pro Stylus printer has various settings: 720 dpi: 1440 dpi: 2880 dpi. It stands to reason that if a non inkjet image is printed at 300 dpi, then using 720 dpi should produce outstanding results as it does. I have printed images at 720 dpi and compared them to the 1440 dpi setting and could not see any difference at all. So it again appears that we would be wasting ink and money to print at the higher dots per inch settings.
When selecting the dpi of an image, we have to ask ourselves if we are going to crop the image or not. Cropping is like zooming in. If I want to zoom in a lot, it would be better to have lots more dpi so that my image will look better. I can take a very poor image and give it lots of MP's and I will still have a very poor image. Therefore you want to increase the image dpi and MP's at the very start of your image processing.
Interpolation:
When you increase the image dpi, the computer program does an interpolation between the true pixel information and the desired one. Interpolation in its simplest form is like adding a number between 3 and 5. The simple answer is 4 and you now would have 50% more pixels. The programs that you can use use a much more complicated process to achieve the end result. There are programs like fractals, etc and claim fantastic results. Again, focus on image quality and don't try to get an image from a 50kb cell phone photo at 72 dpi. There simply is not enough raw image data to get a good quality print.
How to increase the image quality:
Off of the top of my head I can think of at least 3 ways to increase the image quality. Two of these involve Photoshop and the 3rd is by using 3rd party programs like Fractals. I have found that Photoshop produces excellent results and I don't need to use other programs. In the past, best results in PS were achieved in steps. Increasing the image size in 20% steps. If I have several MB's I go straight to the output size which is normally under 20 x 16 inches. That doesn't mean that you can't print 36 x 24 inches. Normally you should have somewhere in the region of 6 MP's but now another factor comes into play. That mysterious black box known as the Printer Driver Software. Information on the PDS is not released to the public and remains a secret.
In the past, I had another 3rd party software printer package known as Q-Image. The authors of this program (now out of business) stated that you were better off using high dpi in the range of 720 dpi and above before sending it to the printer. That is something to think about if you feel that you need to improve an image.
Using Photoshop:
Open your image in Photoshop's Camera Raw. At the bottom of the image you will see your setting listed. Click on this text to pull up this image.
This is a very important setting list for users of PS. I prefer to use Adobe RGB color space as it is much larger than sRGB and you can get it printed at most locations. A bit depth of 16 is preferred when working on your images. All 12 and 14 bit image will be sized to 16 bits. Printing will occur at 8 bits. Now you can see the size drop down box. Click on it and you can increase your image to 25.2 MP's. Select the pixels per inch to say 720 ppi. I am not going into the difference between dpi and ppi. The image will open in PS at 144 MB size verse my normal size of 120 MP's. At this point you are now more concerned with the ppi or dpi for printing purposes. If you want more ppi go into the Image/image size and your can increase the ppi and or the actual pixels in the image. I would recommend keeping the locked ratio set.
You can see that you also have a drop down list to select the best method that PS will use to interpolate your image. Look at the picture size. It is almost 700 MB's. Now duplicate this so you can begin to work on it in PS and your image size goes to 1.35 GB. Crazy. At this point you can crop the small area that you are interested in to begin your work.
Summary:
With the new high MP cameras, many people have resorted to shooting in medium or low JPEG settings to reduce the file size. Just image working on 1000 wedding photos with 1.5 GB's per image. Crazy! I would recommend that you don't do this unless you want to crop out a section of the image. First find out if you really need to increase the image size at all. Remember that Nikon went from the 36 MP camera to the 16 MP Camera in their top of the line $6,000 body. Again we can say that Marketing is at work here. You can do a lot with a good low noise image. If you are producing work for images at or below 24 x 36 inches prints, then 10 MP cameras work just fine.
I have looked at increasing the image size. There is a great tool in PS to Reduce the images for use on the web. I use it all of the time for my posts, so that you can see the image but you can't print the image. Go to File-Save for Web and Devices.
Masters-Tip: Don't be a pixel popper. Hold your print at normal viewing distance to judge how it looks. Do people look at the great master painters work at 6 inches. The answer is NO, they do not.
Kirk is a Professional Wedding Photographer in Windsor Ontario Canada. In appreciation if you would be so kind as to give a G+ and a Facebook Like KW Masters Photography on his Facebook page.
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