Scanning Resolution

[Larry]

Need some help with scanning resolution. I'm using an HP 5470, and printing on an Epson 1280. I want to scan an old photo - about 2x3, and print it as a 5x7. What resolution do I need to set the scanner to? Thanks.

Larry

[Ed_L]

Larry,

I would suggest scanning it at a resolution of 600 if you have an *optical* resolution high enough. Do not use interpolated resolution, as you don't gain any *real* information. If you only have optical resolution of 300, use that. You might be satisfied with the results. Good luck.

Ed

[jeaniesa]

Hi Larry,

You'll most likely want to print the final 5x7 at 300 dpi for the best quality, so work backwards from that final size to figure out what resolution to scan at. In actual pixels, that final size would be 1500x2100. To figure out the scan resolution, divide the original size into those numbers, i.e. 1500/2=750dpi and 2100/3=700dpi. Use the higher number - 750 dpi - to scan at. Then "resize" the image in Photoshop (or whatever image program you use) keeping the actual size in pixels, but changing the dpi to 300. That should give you at 5x7.5" image.

It may also be possible with the HP scanner to specify the final size (5x7") you want and let the scanner figure out the correct resolution. I think either will work.

Jeanie

[jeaniesa]

What Ed said is true also. If your scanner's highest optical resolution is 600dpi, scan at that and then resize the image dpi to 240 - that should get you a 5x7 image. In most cases, the naked eye can't tell a difference between an image printed at 240 dpi vs 300 dpi.

Jeanie

[Larry]

Thanks all for the info. For Jeainie --- The Epson 1280 can print at 1440 and 2880 dpi. I was going to print at 1440 dpi. Should I do the math using that number, or is 300 dpi just the same?

Larry

[jeaniesa]

Larry, I don't own the Epson, but what I've gathered from other people is that printing a 300dpi image on the Epson printer at 1440 produces outstanding results. You do not want to work with at 1440 dpi image - that would be a HUGE file and overkill. I think the difference here (and someone please correct me if I'm wrong) is that the printer resolution is actually "lpi" or "lines per inch" - which is the resolution it can put dots/lines down on the paper. Does that make sense? -Jeanie

[Larry]

Jeanie,

Forgive me for being so dumb but, I should set the scanner to scan at 300 dpi as opposed to 800 or 1200 say, and that would be quite sufficient.

Larry

PS.. I like the little thumbnails that appear under yours and others names. How do I go about adding one?

[jeaniesa]

Hi Larry,

You're not being dumb. This is a confusing topic - esp. when I try to throw all these numbers at you and expect you to pick out what you need. (Just ask DJ how that worked for her. )

You'll need to scan at a higher resolution than 300dpi if you want the final image to be larger than your original. What you want is your FINAL image to be printed at 300dpi. You said that you wanted to enlarge a 2x3 to a 5x7. In that case, I would scan at 750 (or 800 if that's one of your choices). That will get you the actual pixel size you need to print a 5x7 at 300dpi. But, remember to then resize the image in Photoshop (or whatever program you use) to make it 5x7 at 300dpi - otherwise when you go to print it, you'll get a 2x3 image printed at 750dpi.

If I've confused you more, just say so and I'll try to start over.

Jeanie

[jeaniesa]

The thumbnails under many of our names are called avatars. Some of us (like me) have created our own. Others have chosen one from a fairly large number of options. To set up one for yourself, click on the "user cp" tab up top, then click on the "edit options" button near the top of that page. At the very bottom of the "edit options" page, you'll see a section pertaining to your avatar. I think it's pretty straight forward from there. Let us know if you run into any difficulty.

Jeanie

[Larry]

Jeannie,

Understand. Thanks. I.ll let you know how it came out. I do use Photoshop by the way.

Larry

[Larry]

Jeanie,

By the way, what part of Colorado are you in. I used to live in Cheyenne, Wyo. Haven't been back there in quite a while, and I'm sure it's changed quite a bit. Still have a couple of friends in Leadville, Colo.

Larry

[jeaniesa]

Check out the thread I just started in Salon entitled "Regards from northern Colorado". I live just outside of Fort Collins, pretty darn close to Cheyenne.

Where is Glen Cove in NY? I grew up in NJ - 60 miles south of NYC. Went to school in Vermont (UVM).

Jeanie

[George]

I am using the Epson 1270 and I had same questions in reference to what resolution I should be printing at. Contacted Epson and after a lot of e-mails I got to an engineer who advised me to use 240 or 360 as the resolution when I printed out photographs. I scan the photographs , slides or negatives at the highest resolution available on my scanner. I then use GF software to resize it and set the printing resolution.

I normally use 240, which usually provides all the detail I want, but when I am looking to print small details I use 360. The problem with using 360 is the large files.

George

[jeaniesa]

Well now, someone who actually has "official" information! Thanks for piping up George!

And welcome to the RetouchPro forums!!

Jeanie

[Larry]

Jeanie,

Glen Cove is on the north shore of Long Island, just east of Port Washington, if you know where that is. Pretty area. Looks just like New England, in the fall when you get onto some of the back roads. Vermont is my favorite place on the east coast. We have a place up near Stowe.

And actually, I did wander into the Salon after I wrote my question -- silly me!

Larry

[Larry]

George,

Thanks much. Between yours and Jeanie's help I should wind up with an acceptable print. It does get a bit confusing at times swithching your thinking between scanner and printer resolutions.
To me, anyway.
Larry

[Larry]

Geroge,

Meant to ask you, by "GF" do you mean "Genuine Fractals?" If so, How do you like it?

Larry

[Ed_L]

Hey George, glad to have you aboard. Welcome! Some of the experts are now suggesting that printing a Photoshop image with a resolution of 150 is sufficient for photographic quality (printer set at 1440 dpi in Larry's case). I know there are many who will dispute this number, but my suggestion to Larry (or anyone else) would be to make a print with the Photoshop resolution at 300, and another at 150. Compare the results. The file size of the higher (300) resolution will be 4 times the size of the smaller (150) resolution for the *same size print*, because there will be 4 times as many pixels. You should use the smallest file size that will fill your needs. A smaller file size will print easier, it will run much better in Photoshop, and it will take up less room on your hard drive. The results might be more noticeable with fine detail as George suggests. Just my opinion. You need to make up your own mind after making the comparisons.

Ed

[Larry]

Thanks for the insight, Ed. I'll do that test tonight.

Larry

[George]

Larry and Ed hello, I am glad I found this forum.

First to Larry's question yes by GF I meant " Genuine Fractals". I have been using it for over three years and really like it. It must be pointed out that to get good results then the scanned image must have good details and be scanned at a high resolution. I mainly scan from negatives, some times slides. I scan these at 2400 resolution and twice the size of the 35mm negative or slide. This gives me very large files, but does allow me to enlarge them up to 12 x 18 with little or no loss in details. I can not print large than this so I am not sure how large one could blow up a image and keep good detail.

Ed about the resoultion used for printing, in addition to the engineer at Epson, I have talked to a number of other technicial individuals and based on a number of test that I conducted over a period of time, I have found (they had advised this) from my test that the printing resolution should be a even division of the printing resolution of the printer. I am using an Epson 1270 which has a resolution of 1440 by 720 dpi . When I divide this out to get an even number I come up with 180 (8 divided into 1440), 240 (6), 360 (4), and 720 (2). If I was using the 720 printing resolution I could use 120 (6 divided into 720) 240 (3) or 360 (2). If your printer was printing at a resolution of 600 then the input resolution could be 100,150, 200, or 300.

In my test I lost a lot using the lower figure of 180 when printed at both 720 or 1440 dpi. When I went to 240 I got good results at both 720 and 1440. When I used 360 I could see with the help of a 8X Lupe better detail in the smaller parts of the print. Especially when printed at 1440, using print profiles to match the paper being used. As I said this does create some large files. I even tried a large file at 720, could not tell any difference from the 360 setting, but created a file of over 480Megs, which really slowed down the printing. I would never use that high a resolution, in my opinion it does not give me any better print that the 360 does.

I normally print using a resolution of 240 at either 720 or 1440 depending on the subject, and switch to the 360 when I feel I need it to get sharper detail in the smaller parts.

I must also turn on no color change and turn off the high speed printing on the printer.

To get around the large file storage by putting the master copies on CD's and I have installed a second 20 gigabit hard drive to use as a sratch file and to store the images I am working on. My primary disk is 38 gigabits and I keep the operation sysyem and other software on it. I do use it ffor working images some times.

Hope this helps answer the question.

George

[Ed_L]

Very interesting George. Thanks for the input.

Ed

[Larry]

George,

Thanks for the in-depth explanation. One more question for you though. How did you arrive at the numbers you divide into the printer resolutions....(8 divided into 1440), 240 (6), 360 (4), and 720 (2). If using the 720 printing resolution, (6 divided into 720) 240 (3) or 360 (2) ?

Larry

[jeaniesa]

George, Thanks for some GREAT information! I'll definitely be keeping that handy for whenever I get a new printer (most likely an Epson 1280). -Jeanie

[George]

Larry:

The numbers were given to me by both the Epson engineer and the other technical individuals I talked to. They all recommend the 240 or 360. In the discussion they they said the lower numbers did not work as well and the higher number created a file that was to large in regards to any improvement in the print, so I decided to test all of them. My test just proved to me that the 240 and 360 they recommended really worked best for what I was doing. I am not sure how they came up with the numbers.

My prints also improved when I loaded the Epson paper profiles, set up Photoshop to proof in these profiles and then print using the profiles based on the paper type I was using. I print using the Epson matte paper most of the time.

George

[Larry]

George,

Thanks for the info. I'm using an Epson 1280, and I love it. I downloaded some profiles from a web site, and they work great. I also do some printing to cloth canvas. Using the profiles I downloaded they are nearly a perfect match to what I see on my screen.

Larry

[Ed_L]

Hey Larry,

Cool avatar!! But ya better be watching for Wylie! I don't suppose you remember where you downloaded the profiles from, do you? I'd like to check it out.

Ed

[Larry]

Ed,

Thanks, and you're right, I really don't remember. I believe the site was a link to one of the PS sites. Be glad to email them to you if you want. Let me look through my bookmarks too, and I'll let you know if I find it.

Larry

[Larry]

Ed,

Go to this site for the profiles.

http://www.rgbnet.co.uk/ilyons/media...ia_print_1.htm

Larry

[Ed_L]

Thanks Larry. But you didn't have to go through all that trouble. I *will* have a look. Thanks again.

Ed