AboutBill Edwards Expertise Professional Digital Still Photography and Film Questions on Lighting, Equipment, Portraits, and Limited Commercial Still Photography.
Experience 30 years as a professional photographer / business owner
Organizations Professional Photographers of America
Guild of Professional Photographers of Delaware Valley - Past President and Chairman of the Board
Publications Have taught photography at all levels Including Lectures at Professional Photographers of America's National Convention; International Professional Photography Guild's National Convention; State and Local Associations
Education/Credentials Numerous classes and seminars - no degree.
Awards and Honors International Photography Hall of Fame Exhibit Winning Entry
Image Published in Fuji Film's Showcase Publication
Best of Show Portrait of a Child - GPPDV
Best of Show Portrait of a Group - GPPDV
Voted best in Bucks / Montgomery County several times
Past/Present Clients Clients are mostly individual Families local to Bucks and Montgomery Counties in Pennsylvania with several regional clients from Connecticut to Florida. Our studio has raised over $150,000 for local schools and other charities.
Expert: Bill Edwards Date: 4/1/2008 Subject: Minimum dpi
Question What is the least amount of dots per inch I can have without the picture becoming grainy. My picture in question is 3008 pixels wide by 2000 pixels high @ 300 dpi. I need the picture to grow to 30"x20" which would drop my dpi to 100
Answer Donny,
Welcome to my first response on "All Experts". Hope it's good for you.
Right off the bat - I would say that there is no problem printing your image to a 30x20 in regards to pixels anyway. Other factors, of course, may prevent you from getting a decent print. Here are the details. . .
- Obviously it would have to be a properly exposed image. If you had to do a lot of lightening especially - this could cause lots of noise / grain.
- The camera and lens combo can also affect the outcome - what type of camera / lens did you use?
- Sharpness - at 100% magnification - how does the image look on your screen? If you had to add lots of sharpening to the image this will also degrade the quality (making it noisy / grainy)
- Do you (or does your lab) have a good 'rip' software. Most pro and commercial amateur labs are well suited to handle some interpolation (up-sizing of the image). This can make ALL the difference in the world. If you are printing this yourself you may have rip software on your printer or in the software that sends the image to the printer.
I've done plenty of prints at 100 dpi or under with spectacular results. If I'm a little nervous about too low a dpi I have created an Action in Photoshop which ups the resolution by 10%. You can run this 3 - 4 times without degrading the image - BUT never up-res more than 10% at a time. Here's how to up-res in Photoshop:
1 - go to "Image/Image Size" in menu.
2 - Check all three boxes available towards the bottom
3 - Change the 'pixels' selection in the top most drop down box to 'percent'
4 - type 110 in one of the boxes to the left of 'percent'
Viola! - your image now has 10% more pixels! Like I said you can write this into an action if you are so inclined OR just repeat the above steps but NEVER try to enter more than 110 at a time and I don't recommend more than 4 times.
Good Luck with that.
Bill Edwards
Information overload? Just bring it to a qualified custom printer - they will know exactly what to do. There's a guy near me who does a decent job and takes orders via the internet at www.nycv.com - my prices for this are higher for a higher degree of effort and expertise: www.coolstudio.com/expertcustomprinting/ES%20Printing%20Services.pdf
Otherwise the local costco or other amateur lab can give you satisfactory results without any customization or intervention.
