This section of our website is dedicated to better educating our clients concerning both digital and optical imaging.  An always expanding page, this section will be added to as we receive questions from you.  We, at Kula Photo, hope that this service will aid you in your understanding of photographic imaging.  If you have a specific question, e-mail it to us and we'll add it to this page along with its answer for the benefit of all of our valued customers.

 

QUESTION:  When I'm having my negatives or prints scanned, how high a resolution do I really need?

ANSWER:  For most applications 300dpi at output size is more than adequate for excellent results.  The important factor to keep in mind when scanning is not only the dpi number but also the output size.  An example would be scanning your negatives to create 4x6 photos for your photo album.  A "Low Res" scan at most imaging outlets would be more than sufficient.  Ask them what the low resolution scan actually is.  If it is in the range of 300dpi @ 4x6, use this scanning resolution and save not only money but also time in opening these files for your use.   Don't be talked into "Hi-Res" scans that you may not need.  As long as you scan at 300dpi at your output size you should never run into problems.

QUESTION:  Why should I be concerned with image proportion when ordering my prints from a photo lab?

ANSWER:  How many times have you sent your film or digital files to a photo outlet only to receive prints that had a portion of your original image missing?  This is the direct result of not taking the proportion of your image into consideration when ordering prints.  An example of this problem is pictured below.  This theatrical publicity image was sent to us to make up several 8x10 sized photos from a supplied 35mm negative.  The 35mm film format has an image proportion of one by one and a half which does not fit the proportion of an 8x10 print.  Without cropping instructions this image when fit into an 8x10 area lost image area from the original 35mm negative as seen below. This is because a 35mm negative scales proportionally to 8x12 rather than 8x10.

The shaded areas in the above image show clearly the amount of image that would have been lost to make a full 8x10 from this 35mm negative. As can be seen in the above example, one of the cast members has been entirely omitted from the original 35mm image area.  To correct this error either an 8x12 or a full frame 8x10 (7x10 from 35mm) must be ordered to retain the entire image.  In this instance the theater company chose to go with the larger 8x12 print size.  To avoid cropping of your images when ordering prints, always check to see if your image fits "proportionally" into the size print your ordering.  If not, then cropping of the image will occur.  If in doubt always ask the lab you use if your negative or file fits the format for the print size your ordering to avoid "surprises" when you receive your order.

QUESTION:  Your lab accepts either tiff or jpeg formats for printing.  Which should I use?

ANSWER:  In most cases jpegs are fine since they are of smaller file size and can be transmitted to us more quickly than tiff files.  However there are some drawbacks to using jpeg files - files that have become the common language of picture sharing between friends, family and co-workers. 
       First and foremost, jpeg images are "lossy". In other words, digital images saved in jpeg format are compressed to save space and in doing so information is lost along with some image quality.  The jpeg format exploits subtle but important limitations in human vision: Most people have trouble accurately perceiving small changes in color between objects that are in close proximity.  Consequently, the jpeg format is designed to discard small amounts of color information between adjacent pixels on the assumption that you won't be able to perceive what was lost anyway.  As an example, an original image saved in the tiff file format might be just shy of 2MB.  Saved as a jpeg, this same image takes up a mere 500KB, a quarter of the original size.  If you could look at the tiff along with the jpeg, would you be able to see the difference?  Possibly, but you'd have to look very hard to find it.  However, this jpeg image is at the lowest compression level.  The more compressed the file becomes print quality loss becomes apparent so be careful how much compression you use when creating jpegs.
      You should also avoid recompressing your image files. Suppose you take a picture and load it into your image editor.  If it started as a jpeg in your digital camera, it has already been slightly compressed.  When you make changes to the picture and save it again as a jpeg, you're compressing it even more and discarding additional color information.  If you do that frequently enough with this image, the changes will become obvious as exampled below.

section of an original jpeg image

section of same jpeg after several ajustments and saves in the jpeg format I

How can you avoid this?  Save your edited images in the tiff format which is a lossless format.  When you use the tiff format you lock in the image's current level of quality without doing any further damage.  An alternative is to save your edited image in the jpeg format with the compression level at minmum.  If you do that, any loss in image quality probably won't be visable to most people.  And remember that just opening, viewing, copying, or moving jpegs doesn't degrade them.  It's only when you make changes and save again does the potential for damage occur.