×
INTELLIGENT WORK FORUMS
FOR COMPUTER PROFESSIONALS

Contact US

Log In

Come Join Us!

Are you a
Computer / IT professional?
Join Tek-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Tek-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

PRINTING RESOLUTIONS

ò Printing Resolutions! by SPYDERIX
Posted: 1 May 02 (Edited 26 Jun 03)

One question that is coming up a lot is:
"How do I determine printing resolutions, and the size my picture will print?"

*Please note - DPI is the same as Pixels-Per-Inch (px/inch)

-----------------------------------------------------------
Step-1 (Where are you going to use your pictures?)
-----------------------------------------------------------
If you are making pictures/graphics for professional use in brochures, posters, etc. and wish to send your pictures off to commercial printing companies for printing - set your resolution to 300 DPI.

If you are printing your work just to have around the house or share with friends or family and you are printing with your in-house ink-jet or laser printer - set your resolution to 150 DPI.

If you are making pictures for use on the Internet - set your resolution to 72 DPI.

-----------------------------------------------------------
SOME BACKGROUND INFORMATION!
-----------------------------------------------------------

How does resolution and print size, and # of pixles all get used?

There is a formula to figure this out:

PRINT SIZE  X  RESOLUTION  =  # OF PIXELS

Alternatively you can re-arrange the formula to suit your needs. See examples below.

Also this can be used for both px/cm and px/inch, make sure you use the correct units when using the formula. If your print size is in inches then your resolution must be in px/inch, and if your print size is in cm, then the resolution must be in px/cm.

-----------------------------------------------------------
Step-2 (What images are you going to use?)
-----------------------------------------------------------

If you are starting from scratch and you are making a graphic, then at the New Document Dialog box, you can just enter in the size in either cm or inches and set the resolution to whatever you want. *Note- This is the highest resolution, you won't be able to add resolution to your image. If you do add resolution to it after it is finished by just copying and pasting it into a new document, then when you print, the picture will actually be smaller than you intended, so make sure you know where these images are most likely going to be printed, before making your decision.

If you plan on printing pre-made pictures, then as mentioned above, you won't be able to add resolution to it, b/c the printed picture will get smaller. First off, you need to know the size you want your final image to be when printed. To figure out the desired resolution for a pre-made picture you will need to use the formula, but it will need to be re-arranged as follows:

# OF PIXELS
------------- = RESOLUTION
 PRINT SIZE


-----------------------------------------------------------
Examples:
-----------------------------------------------------------

EX-1: I want to create a new Image: 5cm X 6cm and set my resolution to 300px/cm. All I have to do is input the sizes, in cm, and set the resolution to 300px/cm, then, when I print the image out, it will print at 5cm X 6cm. Also if I had created this image at 100px/cm, the image would still print out at 5cm X 6cm.

EX-2: I want to create a new Image: 2 inches X 1.75 inches and set my resolution to 100px/inch. All I have to do is input the sizes in inches, and set the resolution to 100px/inch, then when I print the image out it will print at 2 inches X 1.75 inches. Also if I had created this image at 300px/inch, the image would still print out at 2 inches X 1.75 inches.

EX-3: I am creating a wallpaper picture 1024px X 768px to go on the desktop of my computer, and I set the resolution to 300 DPI, but how big will it be when printed?

Re-arrange the formula
# OF PIXELS
------------- = PRINT SIZE
RESOLUTION


Therefore:
1024px
--------- = 3.413 inches
300 DPI


and...

768px
--------- = 2.56 inches
300 DPI


So my wallpaper graphic is only going to print out 3.413 inches X 2.56 inches.

*note - you can use px/cm for resolution, but your print size will be in cm.

EX-4: I have a 500px X 500px photograph @ 100 DPI, and I want it to print out at 2.5 inches X 2.5 inches, so I'm going to free-transform my image down to 250px X 250px @ 100 DPI.

NO! DON'T DO THAT!!!


The ability to print your images smaller without having to free-tranform your picture/graphic down is the only way that increasing resolution on pre-made pictures can be used to your advantage. You see, why free-transform the picture down and keep it at the same resolution to print the image out at the desired size, when you can just boost the resolution on the original image, making the clarity much better and still at your desired size.

Re-arrange the formula:
# OF PIXELS
------------- = RESOLUTION
 PRINT SIZE


Therefore:
   500px
------------ = 200 DPI
2.5 inches


So I set my image to 200 DPI to get the correct size that I want, and the clarity of my image is the best it can be, because it is at the original size, and it hasn't been scaled down. (more pixels per inch results in a crisper image.)

*But remember: Increase in resolution on pre-made pictures equals a decrease in actual print size.

CHART OF EXAMPLES:

EX:   print size         # pixels     resolution
  1     5cm*6cm        1500*1800     300px/cm
  2     2in*1.75in         200*175      100 DPI
  3     3.413in*2.56in  1024*768     300 DPI    
  4     2.5in*2.5in        500*500      200 DPI


------------------------------------------------------------
EXTRA THINGS TO NOTE!
------------------------------------------------------------

You may now be thinking, "Oh, ok if I set the resolution too high then the picture will print out really small, but what if I lower the resolution, will the picture get bigger?" Yes, it will! However, listen to the extended version of the acronymn DPI - - "DOTS PER INCH". If you lower the resolution, then you will get fewer dots per inch and the picture will start to look pixelated, resulting in a loss of clarity when you look at your printed version.

------------------------------------------------------------
SCENARIOS: (regarding equivalencies)
Lets say you are creating an image but your editor doesn't support the input of cm or inches. Use the base formula:
PRINT SIZE  X  RESOLUTION  =  # OF PIXELS

Lets now assume your editor only inputs in inches and the resolutions are only displayed in px/inch, but you need to create your image in cm's and px/cm's. Knowing your cm & px/cm can help you calculate inches & px/inch, with the following equivalent:
px/cm X 2.54 = px/inch

and the reverse...

px/inch
-------- = px/cm
   2.54


*note that all this equivalant is doing is converting cm to inches and vice versa. To convert cm to inches, simply remove the "px/" out of each equation above.
------------------------------------------------------------

Also a quick note on scanning photos/pictures and what resolution to scan things at. I always scan pictures in at 1200 DPI. There are 2 reasons for this.

Reason-1: If the picture needs to be doctored (ie- airbrushing skin blemishes off pictures) or (you need to get rid off something quite big and noticeable), then it is best to do that when the picture is really big, then as you shrink the image down, the spot that you touched up will become immpossible to find, and/or may not exist anymore, b/c it has blended in with the picture. Also Photoshop does the best free transform job I've ever seen in regards to making pictures look like they haven't been scanned in.

Reason-2: Like I said earlier, you can't add resolution to images, so if you scan the picture in at a high resolution, then you will still have the opportunity to create a document with a large print size and use a nice high resolution, because the document already has a large # of pixels.

------------------------------------------------------------
Paper!!!
------------------------------------------------------------
  • 5% of your work is understanding resolutions and print size

  • 75% of your work is creating your artwork

  • 20% of your work is PAPER
In order to print prestine images, you will need to use a high quality paper.
I would recommend 60-100lbs. glossy photo quality paper.

------------------------------------------------------------
Thank-you to viol8ion and FUNKYMONK.
------------------------------------------------------------



NATE


http://www.mainframe-webdesign.com

Back to Adobe: Photoshop FAQ Index
Back to Adobe: Photoshop Forum

My Archive

Close Box

Join Tek-Tips® Today!

Join your peers on the Internet's largest technical computer professional community.
It's easy to join and it's free.

Here's Why Members Love Tek-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close