Go Back   Steve's Digicams Forums > Software > Editors (Photoshop, Vegas, Final Cut Pro, Kdenlive, etc.)

Reply
 
Thread Tools Search this Thread
Old Apr 1, 2005, 6:43 PM   #1
Member
 
Join Date: Oct 2004
Posts: 33
Default

Ok, I have a landscape picture taken with a Digital Rebel, now I want to blow this picture around 26 inches by 12 inches and make a print to be hang on a wall. Will Adobe Photoshop will help me to do this? If I understand correctly once I start to zoom my picture it will reduce the quality? Or I can resizethe image to my required measurements?
Mr.M is offline   Reply With Quote
Sponsored Links
Old Apr 1, 2005, 7:25 PM   #2
Senior Member
 
BillDrew's Avatar
 
Join Date: Jun 2002
Location: Hay River Township, WI
Posts: 2,512
Default

Assuming the long dimension is 3072 pixels, printing it 26 inches will yield 118 pixels/inch. Although you will find a large number of discussions/rants/sneers/wild claims/... about the pixel density needed, a minimum of about 200 ppi seems to be a fair reading of the consensus. The number needed depends on a lot of things such as viewing distance and the amount of detail in the photo. In general, landscapes have a lot of detail so can use a higher value of ppi.

You will be pushing it to print that large. There are techniques and programs that help, but if the detail isn't there in the first place, nothing will put it in. Might or might not work. Likely not.

Do some experimenting. Crop out about a quarter (linear) of the photo with the most amount of detail. Try upsizing, sharpening, voodooing, ... and print it six inches long. Do some reading and try stuff. Much cheaper than lots of large prints.
BillDrew is offline   Reply With Quote
Old Apr 1, 2005, 7:54 PM   #3
Senior Member
 
Join Date: Oct 2003
Location: Indian Rocks Beach, FL
Posts: 4,036
Default

You will end up with about 118 PPI expanding your width to 26 inches. That isn't too good. You can get a very slight improvement in your upsample by using SI, Genuine Fractals or the new resample filter in QImage. Your hear some stupendous claims for some upsample products, but you are still getting a 118 PPI image that looks slightly sharper than if you just use bicubic in Photoshop or Lanczos in Irfanview. And if you sharpen the bicubic upsample properly the difference isn't really that much.

As long as you are going to resample you might as well use 300 PPI. That smoothes out the print a little, but you still have a 118 PPI image.

You might try stair interpolation (SI) with Photoshop. It does at least as good a job as Genuine Fractals. Start an action and do 4 or 5 resamples at 5% increase. You can then apply that action until you are just over 300 PPI for the 26 inch width. It doesn't sound very intuitive but it works at least as well as any resample you can do. I have an action combining three of the first action, but it isn't that much hassle to apply the action a few times.

You can run out of RAM with SI. 10% increases instead of 5% are almost as good and stress the RAM less. It also takes less time. If I were making a large print for the wall I would take the time to use the 5% increases.

No matter how you upsample you will likely have to do some sharpening. I like this tutorial if you don't have a dedicated sharpening plug-in: http://www.luminous-landscape.com/tu...rt_sharp.shtml

If you can take the shot again do a multiple shot panorama to increase the resolution.

Some saturation increase is also often needed with low resolution blow-ups.

Edit: Didn't see Bill's post. I agree that you would do well to experiment on smaller prints and just use a section at your final resolution.



slipe is offline   Reply With Quote
Old Apr 2, 2005, 10:57 AM   #4
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

FWIW, I know someone that had an image that was less than 3 Megapixels after cropping, that was printed at 20x30" size a while back. They were quite pleased with it.

In this case, the printer did the necessary interpolation, advisingnot to prepare the image by interpolating it first (the printer claimed that they could do a better job with their software).

Here is the printer used:

http://www.elcocolor.com/hot_internet_only_specials.htm

Here is what they have to say about it:

Quote:
SHOULD I UPSIZE OR RES UP MY IMAGE? NO! WE KNOW THERE ARE A LOT OF STAIR/STEP INTERPOLATION ACTIONS AND SOFTWARE OUT THERE AND THEY MAY WORK GREAT FOR MAKING PRINTS ON YOUR INKJET PRINTER, BUT THEY ARE NOT BETTER THAN OUR RIP. SAVE YOUR TIME AND LET OUR RIP DO THE WORK.

http://www.elcocolor.com/posterspecialfaq.htm

Of course, this printermay be the "exception to the rule". With many printers, you'll probably want tointerpolate the images first as Slipe suggested. Otherwise, you'll get pixelation.

Viewing distance also comes into play, since you typically don't view a larger print from as close. At close range, you could see some problems with it (sharpening artifacts, etc.) Subject type can be a big factor, too. Landscapes with a lot of detail are probably not the best choice for trying this (huge print from lower resolution image).

In this above case (20x30" printfrom less than 3 Megapixels)the scene was a sunset with mountains. The mountains did not have anything in the way of foilage that would have made the lower resolution stand out as being insufficient (and they were more like a silhouette in this photo).

As BillDrew suggested, you can test how well an image will print by taking a crop of the image, then printing it with the same number of pixels per inch that you would be using for a larger size. Then, view it from the same distances you expect to view the larger print to see how wellit works.

Lin Evans has some very good posts on this subject (how large can I print), explaining why some subjects work better than others. Seethe two posts from Linin this thread:

http://www.stevesforums.com/forums/view_topic.php?id=9501&forum_id=37

JimC is offline   Reply With Quote
Old Apr 2, 2005, 12:30 PM   #5
Senior Member
 
Join Date: Oct 2003
Location: Indian Rocks Beach, FL
Posts: 4,036
Default

If I were having a large print made for my wall it would have subtle Photoshop work done. While I agree that their "Rip" on a multi-megabuck printing setup might upsample better than I can, it would also have to sharpen an upsampled image. I would much prefer to do that myself in specialized software and to my taste. Sharpening has to be done last, and it is very important that automatic equipment not add to that sharpening.

Methods like Genuine Fractals and SI actually end up adding some artifacts to make the image look sharper. Neither actually do an unaltered upsample. I would guess the "Rip" upsample does something similar. If you upsample with bicubic and are good at sophisticated sharpening in Photoshop or have good specialized sharpening software you can do as well as any system that does a sharpen while upsample process.

I would send my image at around 300PPI with specific instructions to not allow the printer's equipment to make any alterations except the necessary spooling. I would want it done my way and not theirs.

Having said that, I think many people would do better sending the unaltered cropped image and having a printer with good automated equipment take care of the details. Comparing scanned negatives to prints from the photofinisher I'm always impressed at how often they do a great job of adjusting less than perfect images.


slipe is offline   Reply With Quote
Old Apr 3, 2005, 12:02 PM   #6
Member
 
Join Date: Oct 2004
Posts: 33
Default

Thank you guys for all good info and knowledge youpost up here!
Mr.M is offline   Reply With Quote
Old Apr 3, 2005, 12:38 PM   #7
Administrator
 
Join Date: Jun 2003
Location: Savannah, GA (USA)
Posts: 22,378
Default

slipe wrote:
Quote:
I would send my image at around 300PPI with specific instructions to not allow the printer's equipment to make any alterations except the necessary spooling. I would want it done my way and not theirs.
I'd probably compromise and go 240PPI with it to someone specializing in poster size prints if you wanted to sharpen it after is was rezzed up some.

This printer's FAQ recommends not going above 240PPI if you do interpolate, and does say that it's fine to sharpen it yourself.


Edit.. Make that 254DPI

See the FAQ's menu choice on this page. Of course, this is going to depend on the printer you use.

http://www.elcocolor.com/hot_internet_only_specials.htm

WANT TO UPSIZE MY OWN FILES, CAN I? SURE, BUT KEEP THESE THINGS IN MIND. DO NOT SIZE YOUR FILE LARGER THAN THE DIMENSIONS YOU NEED AT A RESOLUTION OF 254DPI. DO NOT THINK BY GIVING US A FILE AT SIZE AT 300DPI OR HIGHER IS GOING TO YIELD YOU A BETTER IMAGE. THE CONTRARY IS TRUE! NOW YOU FORCE THE RIP TO SIZE YOUR IMAGE DOWN TO BE PRINTED AND INTRODUCE MORE PROCESSING TO YOUR IMAGE. NOT TO MENTION YOU SLOW YOU UPLOAD TIME AS WELL


JimC is offline   Reply With Quote
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 12:41 AM.