Pixels/cm vs Pixels/inch

Hi,
Is there a setting in the Photoshop scripting that determines whether images export in pixels/cm or pixels/inch? The software program that we have written will ask the user for a preferred print resolution (always using pixels/inch), and will then output the images to Photoshop at that preferred resolution. However, for some reason, on some computers it saves the images using pixels/cm. For example, in our software the user may choose to export at 250 pixels/inch, but when they subsequently open the exported image in Photoshop, the image size shows the size as 98 pixels/cm. Changing the Photoshop preferences doesn't seem to affect this in any way.
Cheers,
Ian

Hi Ramon,
Thanks for your suggestion, however the Preferences> Units and Rulers setting does not have anything to do with the Contact Sheet function. The Contact Sheet function itself asks for the Units (which I set to 'cm' as I want to specify the contact sheet dimensions in cm's). The 'Resolution' is a separate setting that I set to 'Pixels/Inch'. I have a friend who is doing exactly the same thing as me and the Resolution gets set correctly as 'per/inch' in the final contact sheet. Their Unit/Rulers preference setting is CM so this proves that it is not related to the contact sheet function.
The reason I don't think that the preferences is the issue is because this behavior is happening on 3 separate installations on 3 separate machines.
I will try this anyway and see how I go?
Cheers
Di

Similar Messages

How can a 200 pixels/cm image result in a 118 pixels/inch PDF?

Hi all,
Just encountered a problem that is a bit puzzling me.
If you create a 1cm by 1cm image in Photoshop, with a resolution of 200 pixels/cm (= 508 pixels/inch), and you save this image to PDF, using for instance the PDF/X-1a presets or one of the Ghent PDF Workgroup PDF presets, the image will be downsampled to 118 pixels/inch (or 47 pixels/cm). This does not compute. When checking the PDF-settings, I would suspect the image would be downsampled to 118 pixels/cm (or appr. 300ppi), as you would believe from the PDF-settings, but not to 47pixels/cm or 118 pixels/inch.
Is seems to me that Photoshop is taking the value (the '118') for the downsampling, but without translating my pixels/cm to pixels/inch first (it just downsamples 200 pixels/cm to 118 pixels/inch), which doesn’t seem very correct to me.
This is a huge problem. If people would accidently use pixels/cm to set their image size, they will end up with a PDF that is not printable and will be rejected by most printing companies because of too low image resolution. I tried to do the same with Adobe Photoshop CS3, but the same problem.
Anyone that can help me try to understand the logic behind this? Below the downsamping settings that would make me believe that I would end up with a 118 pixels/cm image instead of 118ppi and some other screenshots to clarify the issue.
Original image resolution in Photoshop
Image resolution (or preflight error) after saving to PDF

Because it is only 118 ppi or 47pp/cm. Remember: the original image was 1cm wide and had a resolution of 200 pp/cm. The resulting PDF contains only 47 pixels for the entire width (the entire 1cm), so: 47pixels x 1cm or 2,54 inches = 47 pp/cm or 118 pixels/inch. It looks like there were really thrown away too many pixels during downsampling (calculation error in the PDF presets downsampling algorithm).
Actual number of pixels in the PDF (dimension: 1cm x 1cm):

Contact Sheet II Function CS - Resolution altering from pixels/inch to pixels/cm

I am using CS3 with MAC OS X 10.4.11 when I create a contact sheet using File>Automate>Contact Sheet II, I set the 'Resolution' to 72 Pixels/Inch however once the contact sheet is created and I check the image size it has been reset to 28.346 Pixels/cm. This did not happen in CS2
Does anyone know why this is happening? It is annoying as I have to manually reset the Resolution to Pixels/Inch for each Contact Sheet
Thanks heaps
Di

Hi Ramon,
Thanks for your suggestion, however the Preferences> Units and Rulers setting does not have anything to do with the Contact Sheet function. The Contact Sheet function itself asks for the Units (which I set to 'cm' as I want to specify the contact sheet dimensions in cm's). The 'Resolution' is a separate setting that I set to 'Pixels/Inch'. I have a friend who is doing exactly the same thing as me and the Resolution gets set correctly as 'per/inch' in the final contact sheet. Their Unit/Rulers preference setting is CM so this proves that it is not related to the contact sheet function.
The reason I don't think that the preferences is the issue is because this behavior is happening on 3 separate installations on 3 separate machines.
I will try this anyway and see how I go?
Cheers
Di

Adobe Reader default resolution is 110 pixels/inch!?

I have a PC with a 15" LCD, and Windows XP.
Operating system's DPI setting is 96.
I've Installed Adobe Reader and the default setting is 110 pixel/inch (Edit -> Preferences -> Page Display -> Resolution)
This setting makes all images in the pdf I've created blurry.
I don't understand why the default behaviour is to override the OS setting which makes images in pdf files look bad!?

Thanks for the reply.
What's the resolution setting in your installation of Adobe Reader?
I'm actually converting .docx files to pdf.
In Word the pics look great (!00% zoom), but in Adobe Reader they look bigger and blurred (100% zoom).
Then I change the Adobe Reader's resolution to 'use system setting' and pics in reader start to look good too.
I can't force everyone that views the pdf to change the Reader's resolution setting. Whan can I do?

Resolution (pixels/inch) in Photoshop opening window

When I convert a camera RAW image to DNG format (using the Adobe DNG Converter) and open it in Photoshop CS, one of the things I can apparently set a value for in the window that opens is the resolution (in pixels/inch). How can I choose a value? Is this not predetermined by my camera's resolution and then modified by my choice of paper-size when I print the image? I should be very grateful for an explanation.
I am using Adobe DNG Converter v. 5.7 and Photoshop CS on a Mac G4 (PPC) with OS X 10.4.11.

>Charles:P.S. I would like to meet the software engineer at Epson who decided that the "scale your image by an arbitrary amount depending on paper size" option should be called "borderless printing" - I have some mortgage-backed securites I want to sell him.
It isn't just Epson. Virtually all 'borderless' printing engines have overspray. It is to make sure that a slightly misaligned paper does not result in a bad print--i.e. white stripes down one or more sides. In some (very few) printers this 'overspray' can be turned off. In others (a few more) the overspray can be reduced but not eliminated.
>Charles:P.P.S And I'll give the brilliant Epson tech-writer $1,000 for every time the manual mentions that "borderless printing" scales your image
It is another one of those items so obvious to the printer manufacturers that they don't deem it necessary to place in the manuals. Contrary to their beliefs it is not common knowledge and I agree it should be in the manuals.
The 'problem' has been around for a long time:
See: http://www.steves-digicams.com/techcorner/april_2006.html
and scroll down to the section titled "Prints are the wrong size"
There is also a link from that section that delves much deeper into the print size problem:
http://www.steves-digicams.com/techcorner/March_2005.html

Would a photo with 70MB in pixel dimensions but low resolution print clearly?

Hi there,
Here is a snapshot of the image size window:
Is it true that if pixel dimension is very large in size than the resolution number under document size doesn't matter ?
I really woudl appreciate your help in telling me if my photo will print clearely choosing the belwo document size.
Many thanks!

This is the easiest way for you to get an acurate idea of what your image will look like printed...
1) Create a new document the size it will be printed and set the resolution to 300dpi (pixels/inch). (Due to the size you are going for I suggest using RGB instead of CMYK)
2) Open the file you created and (using the 'Move' tool) drag it onto the newly created document.
3) Zoom in to 100% and what you see is what you get when printed.
The distance the print will be viewed from is important however, for example, if it's a billboard the viewer is pretty far so the quality is pretty forgiving and a resolution of 200dpi should work.
Feel free to hit me up and send me one of the pictures and I will give you an acurate judgement on how they will look printed at that size.

Setting image resolution default to pixels/cm?

Hi all,
A small question: is there a way to set PS CS5's default for image resolution to pxels/cm?
In Preferences (with no file open), I've set rulers to mms, and whatever I can I've changed from pixels/inch to pixels/cm. But when I open an image, and go into Image/Image Size, the dimensions show up in mms but the resolution is still always shown as pixels/inch. Yeah, it's just a single step to drop the option down and change to pixels/cm, but I've got a few hundred images to edit (and manually - they're all in different locations!) And it is just easier for what I'm doing to work in cms - it's a consistent 68 pixels/cm, which is easier to set than 172.72 pixels/inch.
Any way to make PS CS5 default to pixels/cm, please? Thanks for any help.

Try setting to cm's instead of mm's in the preferences under ruler units.
One thing, if you change the ruler units on the rulers themselves, then
you might get a different unit in the image size dialog.
MTSTUNER
Message was edited by: MTSTUNER

Pixels and document size differences in Illustrator compared to Photoshop

Why is the pixel ratio of a project in illustrator different than that of the same pixel ratio of a project in Photoshop? Example: A project can in Illustrator can have an artboard of 950px X 950px and be 12in and in Photoshop that same pixel ratio will be 4 3/4in.

The rulers in Illustrator are always with fixed ratio of 1 inch = 72 pixels (72 ppi), you can check this by right clicking on the ruler and choosing inches or pixels and you will see that 950 px will be 13.9 inches and not 12 inches as you stated.
The ratio of the rulers in Photoshop depends on the ppi resolution of the image set by the user in the Image Size dialog box. If choose Image > Image size, and set the Resolution to 72 pixels/inch (ppi) then the ratio of the rulers in Photoshop will match Illustrator. If you set it to something else they will not, in your case with an image with sides of 4.75 inches in Photoshop the Resolution will be 200 ppi in order to contain 950 pixels per side.
When you save an image from Photoshop that contains metadata it has information about the size of the document in inches and pixels. Illustrator will place such images with the size of the inches not the pixels as indicated on the Illustrator rulers, internally however the image will contain all the pixels as indicated next to the PPI on the Control bar under the main menu when image is selected. These internal (actual) image pixels will be used when printing and when zooming on screen to render the image. Also if you copy from Photoshop and paste in Illustrator, it also will paste with the size of the inches and not the pixels (at least this is how it works with CS5 on Windows)
If the placed image is without metadata Illustrator will always place it assuming 72 px = 1 inch (72 ppi). You can check that if in Photoshop save an image using Save for Web and Devices and choose None for Metadata.

Even vector-based layers are pixelated. Why?

The files I am creating in photoshop are all coming out very pixelated lately. Especially after I flatten the image or export it to a pdf. This is true even for text layers, eps files I placed, and vector-based objects I drew. The photo layers are pixelated too, even though they were hi-res to begin with and I only made them smaller when I added them to my document. Any idea why everything is so pixelated? I tried changing the file from 72 to 300 pixels/inch, but that didn't clarify the images. It just smoothed the edges a bit.

As Chris pointed out if you flatten you no longer have any vector graphics, To save your vector graphics you need to save in a layered format. PSB, PSD or Tiff.
You can additionally save different sized non layered image files from your layered document. When you use Image Size to resample you document to a different size vector layers like shapes and text will be resized using vector graphics and pixel layers will be interpolated using the method you set in the image size dialog or your Photoshop preferences interpolation method. It would be best if you use a tool like one of the Image Processor scripts to save these files from your Layer documents files so your layered files are not changed and over written. Some of the Image Processor scripts use Photoshop plug-in Fit Image to do the resizing. Fit Image uses interpolation method bicubic. The newer Image Processor Pro can be downloaded from Russell Browns web site once installed you will find it under menu File>Automate>Image Processor Pro. Its let you set which interpolations methods should be used for different output file sets.

Pixel resolution question for iphoto book

Hi,
I open my photos in photoshop,
the resolution is 72 pixel/inch with the pixel dimensions: 1728 X 2592
Should I change all my photos to 300 pixel/inch (the biggest photo size will become: 5.76 X 8.64 inches, but the pixel dimensions will still be the same)?
Thanks

Welcome to the Apple Discussions.
Just put the photos into the Photo Book template and iPhoto will do the rest.
Regards
TD

Is there a way to get Illustrator to know how many pixels are in an inch?

Hi, this is my very first post so please be gentle!
I've scoured these forums and found no solution to this problem.
I'm using Illustrator CS5 to make graphics for print. I need to print said graphics at 300 DPI, but this seems impossible.
Illustrator has plenty of settings that tell you it's at 300 DPI, but it never ever is.
Here's the new file dialog:
In this example, I'm making an image that I want to print on a letter sized piece of paper. The example is square, but that's not important. 8.5 inches at 300 DPI is 2550 pixels. Watch what happens when I change the unit to pixels:
Despite the raster effects set to 300 PPI at the bottom, it thinks that 8.5 inches is 612 pixels, which is 72 DPI, NOT 300. Watch what happens when I choose the correct pixel resolution then switch it back to inches:
It actually thinks I want to print a 35 inch poster with horrible gif resolution.
You might say that the pixels are the only thing that matters when it comes to print, and you'd be correct, if I didn't want to print via a PDF. When I save a drawing like this at the correct pixel resolution to PDF, then try to print it at the actual size (300 dots to an inch), I get something like this because Acrobat thinks I have a 35 inch high document:
Well, you might say, why don't you just print it to fit and you'll be fine? Sure, I can tell my print dialog to fit it to the page, but it doesn't fit it to the actual page size, it fits it to the printable area, which is maybe an 1/8th of an inch smaller on every side of the page, which means my 300 dots will never fill an inch exactly on my printer. I could never in a million years print a usable ruler.
Before you ask, yes the Document Raster Effects Settings are also 300 PPI and it has no effect.
Does anyone know what I'm doing wrong?

Coming late, and maybe it's covered, but I noticed this earlier quote: ""I use Save As, then choose PDF from the dropdown menu. The actual size of the PDF will be 72 PPI. I can try printing to PDF, and see if it makes the same giant PDF..."
I think you may be getting hung up on resolution when there isn't one. PDF files DO NOT HAVE A RESOLUTION. Like Illustrator files, they are a vector format.
A PDF file might contain no images at all, then it is impossible to talk of resolution at all. Or it might contain images, but these might all be different resolutions. Sometimes, it so happens that all the images have the same resolution, then it is just about possible (but not necessarily useful) to talk about resolution. A number of utilities claim to report the resolution of a PDF but just make it up! Where did you get the 72 dpi figure?
Another common error is to think of "100% scale" as being a universal thing, and expecting something viewed at 100% to be the same size in all apps, so to think something is wrong when they are not. This is simply an error: each app has its own different idea of what 100% means and you cannot compare apps this way.
If you want to know the size of a PDF, first realise each page COULD BE a different size, though they usually aren't. Open in Acrobat and hover the mouse in the bottom left corner until the size appears. This is in inches/mm; remember there cannot be a size in pixels.

I am writing a book to be published. how to i get my pages documents to PDF or JPG or something else that is at least 224 pixels per inch?

i am writing a book to be published. how do i get my "pages document" to a high definition level...at least 224 pixels per inch? i can get to 150 ppi via preview to JPG, but that seems to be the best i can do with my new snow leopard imac.

Hello Barbara,
> i have text written in Pages and these need to be at least 224 ppi.
i also have photo collages that were created in Pages and also need to be at least 224 ppi.
the book has about 60 pages of photo collages and about 30 pages of text.
If you want to print using a digital press or an offset lithographic press at high resolution, then you typography is resolution independent but your photography is not. In other words, you must embed into your Pages document the images in the resolution that is right for rendering in the high resolution raster image processor.
Raster image processors will as a rule of thumb produce good quality detail if you embed photographs with 300 dot per inch resolution. Because raster image processors differ in how they reproduce detail, and because this information is generally not public a rule of thumb principle is applied in preparing the page description for printing.
By default, if you use colour transparency in your work, the system graphics service will detect this and save out PDF 1.4 automatically. However, not all raster image processors have PDF frontends that accept PDF 1.4. For this reason, there is a fallback which you must set up yourself.
If the receiving raster image processor does not have a PDF frontend that accepts PDF 1.4, you have to manually enter the resolution at which the transparency will be rendered. The system graphics service will then render the resolution for you and save out what it technically termed a 'flattended PDF'.
Alternatively, if you don't want to work with the Apple ColorSync Utility yourself, you can send your PDF 1.4 with resolution independent transparency to a prepress operator who will then use specialised software to render the resolution for the specifics of the service he or she is selling you.
If you want to work with the prepress interface in system graphics services, then below is a link to summary on setting up the ColorSync Utility for ISO 15930-3:2002 PDF/X-3. This passes prepress preflight testing in Adobe Acrobat Professional 6.0.1 (the first version that tested for PDF/X-3).
/hh
Reference
https://discussions.apple.com/thread/2738092?threadID=2738092&tstart=0

HT4044 What is the acceptable number of sub-pixel anomalies in the MacBook 13 inch?

What is the acceptable number of sub-pixel anomalies in the MacBook 13 inch?

Actually, I am a technician in training and I was looking for the answer for a discussion I was having yesterday. I was actually looking for the amount of pixels that can be bad in order for the screen to be replaced. Here's what the service manual for the Mac Book has to say:

20-inch Intel Core 2 Duo pixel pitch

Can anyone tell me what the pixel pitch is on the new 20" iMac?
Thanks.

You mean pixel resolution of the iMac's display?
17-inch - 1440x900
20-inch - 1680x1050
24-inch - 1920x1200
All located on Apple's store/Tech specs for the iMac.
-benny

Pixelated/frozen MacBook Pro (13-inch, Mid 2010)

MacBook Pro (13-inch, Mid 2010) is about 3 years old and for some odd reason, the screen becomes pixelated and won't function properly. I read that it could possibly be a problem with something called Nvidia, or it could have something to do with my graphics card failing, meaning I'd have to replace the whole board. I'm not quite sure what to do or even what it could be. I gathered that information from searches both on google, yahoo and on these discussions. Here are some photos of what my screen looks like when it acts up:
Thanks in advance
-Karina

I've got a mid-2010 MB pro 15" and I have exactly the same problem despite the fact I had a previous change of card on the computer but it still work badly. The crash is not the same, but I've got to reboot several times a day

Pixels/cm vs Pixels/inch

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