Author Archives: Jane

5 things graphic designers are supposed to know when it comes to print

In the past decade, I’ve had a few hundred ‘just out of university’ graphic design interns through our door. Some with extremely portfolios of work, some with potential. Each time they have started, I have been astounded as to their almost ignorance of designing for print. They knew fundamentals of typography, white space, colour scheming, etc, however, they are ignorant about basic pre and post design stages.

We have created a list of the top 5 things that 80% of our new designers did not know when it comes to design for print.

1. True Black Color.

When you’re creating the artwork, and you pick black, even when working in CMYK, it reverts to almost black, (#000000 or 75/68/67/90 in CMYK) a default in the color picker. When this almost black goes to print, it comes out looking grey, which means unhappy clients.

Here’s the solution. Go to the color picker, and change the CMYK values to C50 M40 Y40 K100. True black for print, every time.

true black color CMYK value

2. Bleed and Crops.

Bleed is the area of artwork that is extended beyond the actual dimensions of the document. It is used to avoid strips of white paper showing on the edges of your print. That is, a background colour or image should spread to cover the entire bleed area. The standard for the ‘bleed’, the edge around the document that will be trimmed, will be 3mm. This means that every side of your document needs an extra 3mm added on to it. If designing in Illustrator, this is easy peasy japanesey.

bleed and crops

In the Illustrator, open a new document and you will see that there is a space for ‘bleed’. Make sure that this is set to 3mm for each the Top, Bottom, Left and Right, or that the link button is pressed.

set bleed in illustrator

Learn more here, http://blog.spoongraphics.co.uk/tutorials/designing-for-print-setting-up-crops-and-bleed

3. DPI and PPI.

PPI stands for pixels per inch. PPI is a measurement of image resolution that defines the size an image will print. An image that is 1600 by 1200 pixels at 300ppi will print at a size of 5.3 by 4 inches. Or it could be printed at 180 ppi for a printed size of 8.89 by 6.67 inches. The higher the ppi value, the better quality print you will get–but only up to a point. 300ppi is generally considered the point of diminishing returns when it comes to ink jet printing of digital photos.

DPI is better known as Pixels Per Inch, it is the measure of the resolution for printers. And it is often used interchangably with PPI, causing a lot of confusion, however, DPI refers to the resolution of a printing device.

When sending the artwork to print, you want to make sure that your dpi is set to 300. In Illustrator, this can be found on the New Document settings page.

4. PDF Formats.

Most printers will want you to send the final as vector PDF document. Using a JPG or PNG, will make it so that your text is fuzzy and your images less sharp. If you are using a combination of photos and art, then ensure that the photos were 300 dpi when you brought them in.

Printers have diferent requirements for formats (moo.com for example states in their preparing artwork section: ‘Make sure you pre-flight your PDFs using the ‘Adobe PDF/X-1a’ preset. This option can be found in Adobe Illustrator, Adobe InDesign and more recent versions of Adobe Photoshop.’) Make sure you ask your printer before sending the artwork what they prefer. Below you can see the selection for PDF/X-1a.

5. Exporting PDF With Marks & Bleeds.

Your art should have been started with the 3mm bleed on each edge. To make sure that all of the appropriate crop, and printers marks are on the final PDF here is what you do.

1. go to File > Save As, and make sure that PDF is selected in the bottom drop down box.

2. Name your file, and hit Save. This will bring up the PDF dialogue box.

3. On the left hand side, hit the tab for ‘Marks & Bleeds’ Make sure the boxes are ticked for ‘All Printers Marks’, and under Bleed, ‘Use Document Bleed Settings’ Hit Save PDF and you’re done.

bleed and marks set

Wah-lah! Now you should have an exported PDF that has all of the pretty printers marks like this one.

marks pdf print

The print size, pixel dimensions and image resolution of a picture

People always have an illusion about the print size of a picture saw on the computer screen. They believe that the print size and quality will be same as the one they see on the pc screen. If you are one of them and are planning to print some professional quality pictures, the article below is highly recommended.

The print size of a picture can hardly be the same as the one you see on the screen. The monitor resolution play the tricks. Even for the same picture, the size displayed on the screen is different if the monitors have 2 different resolution. A monitor set to 800×600 will show an 800 pixel wide by 600 pixel tall image as a full screen image. On a monitor that is 1600×1200 the image will only take up 1/4 the screen. You might have thought it would take up half, but it’s actually going to be 1/2 as wide and 1/2 as tall (so 1/2 times 1/2 = 1/4). Long story short, the image will look much smaller on that screen even though the image is the same size.

Well, so how do we know the actual print size of a picture since we can not get this information visually on the screen? To get an answer to this quesiton, we need define the concepts below first.

Pixels, short for “picture elements,” are the building blocks that make up a digital image — the tiny individual dots that a digital camera uses to capture a scene or that a computer uses to display images onscreen. A file’s pixel count (or pixel dimensions) is arrived at by multiplying its pixel height and width (as in 3000 × 2000 pixels). The Pixel Dimensions section tells us how many pixels are in our image.

The easiest way I can explain image resolution is to say that more resolution means an image displays more detail (or is capable of displaying more detail). It is measured by the pixel counts either from the top to the bottom  or from the left to the right inside each inch of the image. The pixel counts inside each inch from the top to the bottom is equal to the pixel counts from the left to the right. In one word, the resolution (or “res,” for short), is the fineness of detail in a document, and is measured in pixels per inch (as in 250 or 300 ppi).

While the print size, also called document size  tells us how large the image will appear on paper if we print it.

For now, we have explained pixel dimensions, document size and image resolution. What is the relationship between these 3 factors?

pixel height = image resolution * document height

pixel width = image resolution * document width

Below is a picture I took of a fower by the river. Let’s open it in the photoshop to have a check.

document-size-pixel-dimensions-printing-size

I’ll go up to the Image menu at the top of the screen and choose Image Size, which brings up the appropriately-named Image Size dialog box:

image-size-photoshop

Let’s do the calculation.

1200 = 72* 16.667

800 = 72*11.111

Bingo, all is correct.

Here the image resolution is only 74 pixels per inch. However, if we want a professional quality print, we need increase the resolution to make the image suitable for printing. 300dpi is standard, sometimes 150 is acceptable but never lower, you may go higher for some situations. Image files with higher resolution (more dpi) will also have a bigger file size because they contain more data. Start with the biggest images you can but when putting images on the web they should be set to 72dpi, it’ll save you a ton of bandwidth and they’ll load faster. Yes, they’ll be smaller than the original but should in most cases be plenty big because of monitor resolution (ppi) sizes.

For more information about the resolution, please check the links below

http://www.peachpit.com/articles/article.aspx?p=1660204

http://www.photoshopessentials.com/essentials/image-quality/

http://www.vsellis.com/understanding-dpi-resolution-and-print-vs-web-images/

Image resolution for printing – LPI and DPI

A digital “raster” image acquired from a scanner, a digital camera, or created directly in a “paint” application like Adobe Photoshop is made up of a mosaic of “pixels” (picture elements).”

The physical size of the image is described by two numbers which can be expressed two ways:

1) The number of pixels per inch/centimeter.
2) The number of pixels in both horizontal and vertical dimensions.

Or:

1) The number of pixels per inch/centimeter.
2) The horizontal and vertical dimensions expressed in inches/centimeters.

Those are just two ways of saying the same thing.

Note that I use the term “pixels per inch” – ppi. Very often the term that is used is “dots per inch” or dpi. Technically the terms are not interchangeable – however, in daily usage, when speaking about digital images the terms are considered as meaning the same thing. You may sometimes hear the term “spi” – samples per inch. This refers to a scanner’s resolution – i.e. it ability to acquire an image at so many samples per inch (e.g. 300 spi). Again, in practical usage, when speaking about digital images – ppi, dpi, and spi can be understood as meaning the same thing.

Interestingly, digital cameras typically do not have a resolution assigned to them.

Instead a digital camera captures data based on the “megapixel” ability of its CCD sensor. For example, a 14.2 megapixel camera might capture an image that’s 4592 pixels by 3056 pixels, which equals 14,033,152 total pixels. When you open the file into an image-editing program a resolution must be assigned to the file. Most programs, including Photoshop, use 72 ppi as the default resolution.

Background – halftone dots make the image reproduction

Because printing presses can only lay down 100% ink or 0% ink, digital images acquired from scanners, digital cameras, or created directly in “paint” applications need to be converted into a binary (on/off) format. This is done through a process called halftone screening. The result is that the image will be converted to dots of either 100% or 0% ink with the original tones being simulated, in this case, by the size of the dots. Bigger dots represent darker tones – smaller dots represent lighter tones:

The fineness of the screen, and hence the level of detail in the original that can be preserved, is determined by how densely packed the dots are and is indirectly described by how many rows – or linesof dots are used per inch (or centimeter) to create the image. These virtual lines are highlighted in red below:

The key thing to remember is that although the halftone image is made up of dots – the level of detail that it can reproduce is described in terms of lpi NOT dpi.
So, original image pixel density/detail = ppi, spi, or dpi. Halftone reproduction dot density/detail = lpi.


Of course, in order to pack more lines of dots into an inch – the smaller the dots become and hence the greater amount of image detail that is preserved.

The relationship between dpi/ppi and lpi for grayscale images

The guiding principle for understanding what original image resolution (ppi/dpi) is needed compared to the halftone screen (lpi) that will be used is that the image pixels should always be more densely packed (ppi/dpi) than the detail resolving ability (lpi) of the halftone screen that is used.

This minimum required original resolution can be represented by the formula: 1.5 X lpi = ppi @ 100% reproduction.

This ideal required original resolution can be represented by the formula: 2 X lpi = ppi @ 100% reproduction.

The relationship between dpi/ppi and lpi for CMYK images

As with grayscale images, the guiding principle for understanding what original image resolution (ppi/dpi) is needed compared to the halftone screen (lpi) that will be used is that the halftone screen should not reproduce the image pixels themselves but instead the tones the pixels represent. It is worth comparing these images to their grayscale equivalents in part 3.

This minimum required original resolution for a CMYK image can be represented by the formula: lpi = ppi @ 100% reproduction.

This ideal original resolution can be represented by the formula: 1.5 X lpi = ppi @ 100% reproduction.

This maximum required original resolution can be represented by the formula: 2 X lpi = ppi @ 100% reproduction.

The below table provides image resolution requirements for a variety of typical print applications:

Table of resolutions
Image resolution “gotchas” – where things can go wrong

Whether you are targeting your images for AM or FM screening, there are at least three places where the resolution of the images may be accidently altered:

1) If the image is resized/scaled in the page layout application – it may no longer have an appropriate resolution:
2) If the image is resized/scaled when the file is converted to the PDF format – it may no longer have an appropriate resolution:
3) If the printshop’s workflow is setup to resample incoming documents – they may no longer have an appropriate resolution. Most prepress RIPs are set, by default, to downsample incoming files to 300 ppi/dpi.

For more details, check here.