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Actual inches in Photoshop ruler

Jun 2, 2011 2:48 PM

Hoping someone can help with what I originally thought was a real simple question.  But I’ve looked everywhere online, and the answers get complicated. 

I would like my Photoshop rulers to show actual inches.  Period.  I know how to change the ruler from pixels to inches, but when I do, the “inches” are really about half an inch each.  So then (based on online tips), I play with the resolution, etc. and I can change the size of the “inches” on the ruler, but I still can’t get Photoshop’s “inches” to be real actual inches, as measured with a ruler.  I'm sure I can evetually find the right rez to make an inch equal an inch, but do I have to?  When you buy a ruler at a hardware store, you don't have to experiment with several before finding one that measures inches correctly.  An in ch is an inch on every ruler on earth.  So what am i missing with PS?

How do I get my Photoshop ruler measure an in exactly like a ruler does?  Thanks if someone can help !!

 
Replies
  • Currently Being Moderated
    Jun 2, 2011 3:21 PM   in reply to TomGroupGA

    The measurable size of the rulers depend on the dimensions of the file and your zoom level. It's the only way to have precise measurements inside of Photoshop–the rulers will always change when you zoom.

     
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  • Currently Being Moderated
    Jun 2, 2011 4:20 PM   in reply to TomGroupGA

    It boils down to the pixel resolution of your display...

     

    The ruler will still be accurate in it's on-screen measurements...do you use the measure tool?

     

    If you want the physical dimensions to be "real" then you would need to set your image resolution to be the same PPI as your display. Course if you want print resolution then you have no alternative to using a higher PPI resolution which will alter the physical dimensions of the rulers.

     

    I really don't think you'll ever get a 1:1 ratio of real life dimension to digital file dimension. That's not the way Photoshop was designed to work. I would suggest dealing with image dimension in the "Photoshop Way™" and just learn how to use the rulers the way they work...

     
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  • Currently Being Moderated
    Jun 3, 2011 6:21 AM   in reply to TomGroupGA

    If you know what the native resolution of your display is, you can enter that in Edit > Preferences > Units and Rulers > New Document Preset Resolutions > Screen resolution. If you view the image on another display, though (say, connecting your computer to your large-screen HDTV, or on another computer), you'll be back to square one.

     
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  • Currently Being Moderated
    Jun 3, 2011 8:43 AM   in reply to Semaphoric

    I've had this same issue and by going into the prefrences > screen Resolution i was able to get it ALOT closer... its still not 100 % but its close enough...

    my 2"x2" comes out about 1.8"x1.8" on screen

     
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  • Noel Carboni
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    Jun 3, 2011 9:44 AM   in reply to TomGroupGA

    What you're seeing in the ruler is what will be an inch when printed at the current ppi value.  What's wrong with that?  Is that not how it's working for you?

     

    -Noel

     
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  • Currently Being Moderated
    Jun 3, 2011 10:41 AM   in reply to TomGroupGA

    TomGroupGA wrote:

     

    ...An inch is always an inch...

    ...in physical space.

     

    You just don't get that a digital display is not a physical space.

     

    Photoshop cannot possibly know what physical size your display is and render a true inch at 100% view.

     
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  • Currently Being Moderated
    Jun 3, 2011 10:46 AM   in reply to Marian Driscoll

    ...Word!

    Marian Driscoll wrote:

     

    TomGroupGA wrote:

     

    ...An inch is always an inch...

    ...in physical space.

     

    You just don't get that a digital display is not a physical space.

     

    Photoshop cannot possibly know what physical size your display is and render a true inch at 100% view.

     
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  • Currently Being Moderated
    Jun 3, 2011 11:02 AM   in reply to TomGroupGA

    TomGroupGA wrote:

     

    ...I design cell phone graphics and I need my PS screen display to appear exactly the same size as the cell screen will be.

    Screen designers (you, web designers, video graphic artists) need to view their work at 100% in Photoshop so that every pixel they see translates perfectly to the digital output device. That means you should be more concerned about the number of pixels wide/high than with physical inches.

     

    Trying to approximate a physical size on your screen means that you will not be viewing your work at 100%... and that is simply insane for a screen designer. You need to evaluate every pixel without the live resampling that occurs when you view at anything but 100%.

     

    Trying to chase after this 1" measure is surely going to screw up a screen artist. What design school taught you this nonsense?

     
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  • Currently Being Moderated
    Jun 3, 2011 11:21 AM   in reply to TomGroupGA

    Semaphoric already gave you the answer, but maybe it's easier for you, with an image:

    screen.jpg

     

    You need to find your screen ppi or calculate it by yourself and enter it there. If you set ps up this way and you click on "print size" when in zoom mode, you'll get a very good result.

     

    Off topic: Agreed with Marian. Your approach is flawed. You need to work at the devices resolution, not on the physical size of the screen.

    Displaying sizes accurately make infinitely more sense when working for print. (like for example checking readbility of small text, prior to making a test print)

     
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  • Noel Carboni
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    Jun 3, 2011 11:28 AM   in reply to TomGroupGA

    TomGroupGA wrote:

     

    Noel, hi.   Yes, when my image is printed, it comes out at exactly the 2x2 dimensions I set up.  So then the question is how do I get my screen display to show the exact same size as what the print/output display will be.  (I realize the problems that will occur for, say an image of 24" by 36" that won't fit on any screen...but I'm talking about a mere 2 x 2 image.)  I design cell phone graphics and I need my PS screen display to appear exactly the same size as the cell screen will be.

     

    Here are my thoughts on that:

     

    1.  Figure out what your exact screen resolution is on your development system's monitor.  Do this by measuring the display and dividing by the number of pixels.  You might get a number like 96 ppi.  Go into Photoshop's Edit - Preferences - Units & Rulers menu and enter that value into your Screen Resolution field for safe keeping.

     

    2.  Figure out what the exact screen resolution on the mobile device is.  You might get a number like 326 ppi for an iPhone 4, for example.  Enter that into the Print Resolution field for safe keeping.

     

    3.  Choose File - New to create a new document.   Set it to the number of horizontal and vertical pixels you want to work with and the output device resolution (e.g., 326 ppi in this example) and before you hit OK, click the [ Save Preset... ] button.  Name it something appropriate like iPhone4 1" x 2".  Keep in mind you might want to do this for a number of different sized images and devices.

     

    4.  Whenever you go into File - New to start a new project, choose an appropriate preset that you've saved, or set the pixel counts and ppi value manually.

     

    5.  While working, examine your design at whatever zoom is comfortable to work at, but remember to look at it at 100% pixel size on the monitor (which will display larger than on the final device) to ensure all your effects are nice and clean.  You can do this, while the Zoom Tool is active in the Tools Panel, by pressing the [ Actual Pixels ] button at the top of the Photoshop main window.

     

    6.  If you want to preview it at the actual size it will show on the target device, press the [ Print Size ] button (you're equating printing with publication on your target device).  Keep in mind your main display monitor is probably nowhere near as pixel-rich* as the mobile device you're targeting.

     

    7.  Do your final review of your graphic on your mobile device.

     

    Hope this helps!

     

    -Noel

     
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  • Currently Being Moderated
    Jun 3, 2011 11:47 AM   in reply to Noel Carboni

    Maybe a small extra tip, based on Noel's step n° 5:

     

    Instead of having to switch between 100% view and whatever zoom level you prefer working on:

     

    window>arrange>new window for xxxx.xxx

     

    I always use this feature as I mostly edit at high zoom levels ( beauty retouching). The extra window allows you to keep track of what you're doing without having to muck about with zooming in and out.

     

    Edit: this was obviously for the OP, not for Noel

     
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  • Noel Carboni
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    Jun 3, 2011 11:51 AM   in reply to Hobotor

    Excellent tip, Hobotor!

     

    -Noel

     
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  • Currently Being Moderated
    Jun 3, 2011 11:56 AM   in reply to TomGroupGA

    ok, I just read you design cell phone graphics. If you click "save for web and devices" you'll find "device central". You can test your designs on different "screens" there. Maybe it's something you should delve into.

     
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  • JJMack
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    Jun 3, 2011 3:25 PM   in reply to TomGroupGA

    I do not know why this thread is so long.

    Calulate your screen's dpi resolution if you do not know it.

    Use menu edit preferences and set the display DPI resolution for the screen you are using.

    Then use menu View and select view print size. Photoshop will zoom your image so 1" will display  1" in size on your display.

    If you set ruler units to inches and set rulers on you will see 1" is 1" in size when you measure it. If you zoom your image to anything other size then print size 1"  will not display 1" in size when measured.

     
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  • Noel Carboni
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    Jun 3, 2011 3:36 PM   in reply to JJMack

    Oops, just got longer with the same info. 

     

    Oops, just got even longer with a meaningless comment.

     

    -Noel

     
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  • Currently Being Moderated
    Jun 3, 2011 3:43 PM   in reply to Noel Carboni

    Oh man, This is an intertaining thread...

    With seems to have some tension... lol

     

     

    "did i just ad to all the nonsense..."

     

    Noel Carboni wrote:

     

    Oops, just got longer with the same info.

     

    Oops, just got longer with a meaningless comment.

     

    -Noel

     
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  • Noel Carboni
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    Jun 3, 2011 4:15 PM   in reply to TomGroupGA

    Did you actually MEASURE your screen, and divide by the number of pixels?

     

    -Noel

     
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  • Currently Being Moderated
    Jun 3, 2011 4:15 PM   in reply to TomGroupGA

    Didn't read the whole thread but saw that it was answered and in case it wasn't mentioned this is how you calculate the screen resolution of your monitor.

    The square root of pixel width squared + pixel height squared divided by (monitor size, for example 24, 27, 30 inches). I have a hotkey for the Print size from the View menu and my rulers in PS are exactly the same size as real life rulers.

    Kudos to the Photoshop team and boo to the Illustrator team who didn't put such feature in the Illustrator preferences.

     
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  • Currently Being Moderated
    Jun 3, 2011 4:16 PM   in reply to TomGroupGA

    Yes as it appears it shows that it is 3" because it is..

    when you print it, it will print out at 3"

     

    But if you stick a ruler to your screen it wont show that, your screen dosent actually know what 3" is; its doing what it thinks the Physical 3"

     

    to be honest it seems your just going to have to live with the .25" difference

    try to zoom your screen 9% and that will turn your 2.75" into 3" (on Screen)

     

    How you will 'zoom' your monitor 9% im not sure... lol

     
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  • Noel Carboni
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    Jun 3, 2011 4:54 PM   in reply to Noel Carboni

    For example, my 20.1" Dell monitor is exactly 16 inches wide.  Coincidentally it's a 1600 x 1200 display.  Hence 100 ppi.

     

    With a 100 ppi setting and 100% zoom, my ruler comes out exactly right on my screen, because 100 ppi is accurate for my display.

     

    JustLeavesWithRuler.jpg

     

    -Noel

     
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  • Noel Carboni
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    Jun 3, 2011 4:24 PM   in reply to emil emil

    emil emil wrote:

     

    The square root of pixel width squared + pixel height squared divided by (monitor size, for example 24, 27, 30 inches).


    NOT the best way to do it!  You don't want to rely on the manufacturer's published monitor size!

     

    Take a tape measure.  Measure the distance horizontally or vertically from edge to edge of the visible display.  Then divide that into the number of horizontal or vertical pixels.  Simple as that.

     

    -Noel

     
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  • Currently Being Moderated
    Jun 3, 2011 4:25 PM   in reply to Noel Carboni

    If you want to do it by measuring follow the instruction on the right side of this link under the image that says 200 X 200 pixels.

    http://en.wikipedia.org/wiki/Pixel_density

     
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  • Currently Being Moderated
    Jun 4, 2011 5:25 AM   in reply to TomGroupGA

    I'm still wondering why we're discussing inches for a screen designer.

     

    Screen designers need to see pixels exactly as they will appear on a device, not resampled to approximate an inch measure. You should not be fiddling with small type if it is being resampled on your screen at something other than the true resolution of the target device.

     

    For clarity, when we say we design for cell phones, what exactly are we designing?

    1. the images that appear on the device's electronic display screen?
    2. printed adhesive wraps to decorate a phone?
    3. printed training manuals or marketing for selling a phone?

     

    Only options 2 and 3 require you to think in inches. If you are dealing with option 1 then you are making an extreme mistake in trying to approximate inches... and everyone here trying to help you with approximating an inch is making an extreme mistake. I thought we all knew better here.

     
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  • JJMack
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    Jun 4, 2011 7:18 AM   in reply to Marian Driscoll

    Marian Driscoll wrote:

     

    I'm still wondering why we're discussing inches for a screen designer.

     

    Screen designers need to see pixels exactly as they will appear on a device,

     

    Still all screen do not display pixels at the same resolution.  An image 300 pixels wide will display greater then " wide on a screen  with a 84 DPI resolution and less the an inch wide on a screen with a 326 DPI resolution.  A screen designer need to design for the display an image will be displayed on.  They may even need have more then one version of an inage and use one the will display well on the device being used.    You can no read text on a 326 DPI resolution screen if the text size used was designed for an 84 DPI resolution device for the text will be too small to see well.  Just because a screen designer can see an image well on his display device does not mean all users will see a useable image they display the same image on their display device.   IMO size matters and DPI resolution is where size is made.

     
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  • Noel Carboni
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    Jun 4, 2011 8:05 AM   in reply to Marian Driscoll

    Marian Driscoll wrote:

     

    everyone here trying to help you with approximating an inch is making an extreme mistake. I thought we all knew better here.

     

    If someone wants to know why something isn't working like they think it should, and they currently think it's magic (or a bug), it's up to us to teach that it's not magic or find out if it really is a bug.  There is always a reason things work the way they do.

     

    -Noel

     
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  • Currently Being Moderated
    Jun 4, 2011 6:19 PM   in reply to JJMack

    JJMack wrote:

     

    ...You can no read text on a 326 DPI resolution screen if the text size used was designed for an 84 DPI resolution device for the text will be too small to see well...

    Are you certain of that?

     

    You'd be making a perfectly fair argument if scaling an image on a 84 ppi screen to the same physical size of a 326 ppi screen would actually allow you to evaluate how readable text would be on that device. But the truth is that Photoshop's display would be resampling the art on the desktop screen so you really could not tell if the text was truly readable on the target device.

     
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  • Currently Being Moderated
    Jun 5, 2011 6:36 AM   in reply to Marian Driscoll

    Using the same resolution to design for a device with different screen pixel density will give you perfect feedback for the absolute detail but physical size also matter in design and may help with avoiding being lost in the details while missing the bigger picture. I would recommend referring to both. For example imagine designing a 16 X 16 pixels icon for desktop screens at a large zoom.

     
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  • JJMack
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    Jun 5, 2011 5:25 AM   in reply to Marian Driscoll

    Marian Driscoll wrote:

     

    JJMack wrote:

     

    ...You can no read text on a 326 DPI resolution screen if the text size used was designed for an 84 DPI resolution device for the text will be too small to see well...

    Are you certain of that?

    Yes it simple math pixel per inch  if an image has a fixed number of pixels and you display it at different pixel per inch resolutions it will display at different physical size.  Think Image Size no resampling change the DPI you will see the print size change. Printers can print at any resolution where displays are run at the native resolution. They are more or less have a fixed resolution where printers ave a varable resolution up to some maximun resolution.

    so and image 300x300 pixels would print 3.571" by 3.571" the snad size that it is on your 20" 84DPI display

    next print it at 326DPI resolution witout resmapling it up in pixel size it will print .92" by .92" the same size it would display on an iPhone.

    That is like 3.8 time smaller. So if your 84DPI displat had readable text in that 3.5x3.5 image the charecters would be is the area 1/8 inch

    when displated at 326DPI these characters would display in an area 1/30 inch. You can see this easily in Phoshop.  Edit a new document 300x300 display ar actual pixels add some normal syze text. Now zoom to 33.3% size can you read the scaled down text.

     
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  • Currently Being Moderated
    Jun 5, 2011 7:46 AM   in reply to Marian Driscoll

    My monitor has 110 pixels per inch and everything looks smaller but at the same time sharper and less pixilated than most of the other monitors. See the difference in the rulers when I displayed Noels's image on my  monitor with my rulers = real life rulers.

    Capture.JPG

    The different options in Clear Type Text Tuner in Windows that tries to reduce pixilated text appearance makes no difference on my monitor because at that pixel density it is already naturally antialiased to the eye. This helps with smaller things like fine text become more readable than most of the other monitors when displayed with the same physical size  but at the same time the eye starts to struggle when reading small size text no matter how sharp it is. In some programs that don't have options for different size text in their menus and UI I'm struggling with reading the menus and have to move closer to the screen. So it is possible to see things better on pixilated large size than on sharp but smaller size. The very fine text on drugs packaging is a good example, if you display the digital files used for printing the text on a desktop monitor at 100% (actual pixels) zoom most people will read it much easier. But it is not all about readability, different physical sizes also may affect composition and color choices for optimized impact. For example a large canvas painting in a gallery may loose its full impact when is printed in an art book, while in the case of a miniature small graphic, there will be not much difference. The challenge is that at zoomed out size on a desktop monitor, even though the pixels in the file are not interpolated they are interpolated on screen and this makes it hard to read and evaluate the actual detail in the actual physical size. So, the best thing is to use for testing the actual device but if that's not possible I would recommend to refer to both using two windows of the same image, one at actual pixels and the other at actual physical size of the end device.

     
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  • Noel Carboni
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    Jun 5, 2011 7:55 AM   in reply to emil emil

    Sounds nice, Emil, what model is that?

     

    -Noel

     
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  • Currently Being Moderated
    Jun 6, 2011 1:19 PM   in reply to Noel Carboni

    Dell u2711. It is the same LG h-ips panel used from the other monitor makes like Apple, Nec, etc. I haven't checked recently, but AFAIK currently  it is still the highest pixel density desktop monitor and is available only at 27 size.

     
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  • Pierre Courtejoie
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    Jun 8, 2011 2:46 AM   in reply to emil emil

    Emil, did you printscreen the page with the compressed image, I get a crisper image if I click on Noel's image to display the real one ( I wish the forum area was wider and would not force a compressed copy on the images posted. Sometimes, the copy is heavier, despite being of poor quality).

     
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