Sunday, July 27, 2014

High Resolution Image for Printing

Need a high resolution image for printing?
What is a high resolution image?
Is my image high resolution? And if not, can I make it so?

Common image files such as jpg, gif, png, tif, psd, bmp, are measured in pixels.

The resolution of a pixel-based graphic is the number of pixels within an inch: PPI (pixels per inch)

Whether the image has high enough resolution depends on the process being used. Generally, offset printers (paper printing) require a minimum of 300 ppi, screen printers (cloth printing) require 240 ppi.

In order to determine whether an image is high enough resolution, you need to know 3 things:
  1. Your image's pixel dimensions (e.g 850 pixels wide)
  2. The printed size desired (e.g. want to print a 4 inch image on paper)
  3. The resolution required by the process your image will go through (e.g. printing 300 minimum ppi)

ASSUMING RESOLUTION NEEDED IS 300 PPI 
If your image is:
(pixels wide)

It can be printed in good quality at:
(inches wide)
100

0.333
200

0.667
300

1
400

1.333
500

1.667
600

2
700

2.333
800

2.667
900

3
1000

3.333
1500

5
2000

6.667
2500

8.333
3000

10

To determine the image's pixel dimensions you will need a program that allows you to do so, such as Paint or Photoshop. Not file size, but rather you need to open the image to see its dimensions.

Your image may look ok on your computer screen (left image), but if it's not the proper size and resolution for your specific printing project, it may print poorly (right image).




If you have an existing image:
To determine what size your existing image can be printed while maintaining good quality, simply divide your image's pixel width by the resolution required by your printer. For example if your image is 850 pixels wide and your printer is asking for 300 ppi: Divide 850 by 300 (850 ÷ 300 = 2.83). Your image can be printed in good quality at 2.83 or smaller. Printing it larger will reduce quality.

Just because an image is very large in pixel dimension and high resolution it doesn't mean it is appropriate for printing. If you take a photo with high megapixel camera and you do something wrong while taking a photo, you are going to end up with a blurry or poor quality photo that may not print well at any size.

To create the right size image image for printing:
To create an image that will be good enough size/quality for printing (example 300 ppi), multiply the size you want your new image to print by 300 ppi. For example if you want a 6.5 print size, multiply 6.5 x 300 = 1950 pixels, You need to create an image that is no smaller than 1950 pixels wide. A good habit is to always start a little larger than you need (Keep in mind very large files are hard to work with and slow to transfer), you can always reduce to the size needed - you cannot enlarge without losing quality.

How can I increase image resolution? With software like Photoshop you can manually increase the size and/or resolution of an image, but that rarely - if ever - improves quality; you are simply adding pixels randomly thought the image. If you have a graphic that is not good enough quality for printing, try image vectorization.

Vector Graphics are not pixel-based therefore they are resolution-independent; meaning a vector file can can be printed at ANY size and not lose quality. To see if your image can be vectorized so you never have to worry about size and resolution, upload your image to my vector-conversions.com

Note: Vector graphics are drawings / illustrations, so the best candidates for vectorization are graphics, logos, drawings, and illustrations, because they can be reproduced in vector format and look exactly like the original or better. Photographs are not suited for vectorization unless you want the photograph to be changed into a drawing.

Saturday, May 31, 2014

Photo to vector for engraving


The only thing I know about engraving is that the vector artwork needs to be created in black and white line-art, and depending on the size of the actual engraving, real small detail should be avoided. There is actually a lot of small detail on the image below and I was sure the engraver was going to reject it but the plaque must have been large enough to hold all the detail. 



Some challenges may arise when changing a multi-color image to black and white LINEART (not black and white grayscale). Elements in the graphic will no longer be defined by different color or shades of gray, they have to be black or white only and you will have to decide which elements are black and which elements are white. Using outlines instead of fills usually works to separate two objects of similar color.





When images are on a color background, removing the background may make the overall feel of the image look different. After playing around with these elements I got a winner.



Monday, May 26, 2014

From Photo to Vector

Here is a recent photo to vector conversion. The project was to change a full color photograph into a simplified vector illustration to be printed using only 3 or 4 colors maximum. (not using the 4 color or full color process but rather 3 or 4 "spot" colors)

The vector file was built with 3 colors: 1. tan, 2. black, 3. red. The gray is a percentage of the black color and can be printed using black ink and "halftone screens". For processes which do not use halftone screens this would be considered a 4 spot color vector illustration: 1. tan, 2. black, 3. red, and 4. gray.


Before online printing exploded as a convenient and inexpensive venue for printing full color, many small printers only had capabilities for printing 1 or 2 color pieces and these were much cheaper than "full color" or "4-color-process" printing. Now most printers can pretty much print anything but there are a lot of processes that still require simplified illustrations with limited amount of colors. Printing on coffee mugs for example (although there are companies like Walgreens that can print a full color photo on a mug), vinyl-cut-stencil-like signs also need limited colors, and the embroidery process are a few that come to mind. Engraving and etching will need black and white only vector graphics - no color.

Sunday, January 13, 2013

Auto Trace vs Hand-Drawn Vector Conversion

Here is a good example of an image that can be vectorized using automated software and it may be acceptable to many customers, yet on closer inspection there is still room for improvement, so for those people whom detail is essential, manual vectorization may be necessary.

 The original raster image is fairly good quality, the pixel dimension is not too small and more importantly there is high contrast between the colors:


See both automated vectorization results and manual vector conversion. At a glance both seem acceptable vector drawings:


But a closeup of the auto-trace results shows some of the detail in the faces is gone. A person with elevated attention to detail will not find this vector conversion acceptable.

Closeup of hand-drawn vector conversion. Note the little noses have a better resemblance to the original artwork:

So taking a few more minutes (or paying a few more dollars) to manually redraw this simple vector image may be worthwhile.

See more samples
20% OFF one vectorization. Code BLOG032013. Only one per customer. Expires March 31, 2013



Saturday, July 21, 2012

Manual Vectorization vs Automated Vector Tracing

To vectorize a raster (bitmap) image into vector format you can either do it by manually drawing node by node using vector drawing software or you can use automated tracing tools within the vector editors. In Adobe Illustrator - which is what I use - the auto-trace tool is called "Live Trace".

Auto tracing is great and almost instant, just a couple of clicks and you are done, so you can save tons of time and money, but automated tracing doesn't work well with all images. It really depends on the original bitmap graphic; the quality, the contrast between colors, even the size. I think the perfect candidates for automated vectorization or auto-tracing are images that are:
  1. Non-geometrical "free flowing" shapes - like the sample tree below
  2. Large, good quality originals that are black and white or high contrast colors with very clear distinction between each color.
  3. Photographs that do not need to be changed to simple line drawings 




The images that will most likely need to be vectorized manually to have a good result, are images with geometric shapes, poor quality originals and images with color blends and gradients. See the difference between auto-traced vs a manually drawn vector graphic:

Samples of photographs vectorized by auto-trace
Samples of photographs vectorized manually and changed to line art
General vector conversion samples

Thursday, July 5, 2012

Vector Conversion of Photographed Artwork

If you need a graphic vectorized but you do not have an electronic file of the graphic, even if all you have is a photograph of an item with the artwork printed on, embroidered on, or otherwise visible on the photograph, we can try to reproduce it in vector format. See samples below.






When photographing artwork that is on a 3 dimensional item like a coffee mug, a hat or even just a flat sign, the actual artwork will be somewhat distorted in the photograph so it is always better to reproduce a logo using an electronic file of the actual graphic such as a scan of a printed logo, but when this is not available we try to correct the vector file as much as possible. See sample below:



More info here

Tuesday, February 7, 2012

What The Font?!

Do you spend countless hours trying to identify fonts?

If you work in the graphic industry like sign-making, specialty printing, screen printing, engraving, etc., you probably have had to re-create a graphic in vector format so that you could use it with your machinery.  I vectorize all day long (convert raster images into vector art) and I used to spend countless hours trying to figure out which font was used on the original graphic so that I didn't have to manually and painstakingly redraw each letter out. I had customers wonder why a simple plain text graphic would be quoted higher than let's say an image of a tree with no text. It used to take me an hour to go through my font catalogs only to find out that I did not have the font or that perhaps it wasn't even a font but custom-made text instead.

But that was before I discovered What the Font?! What a great website! You simply upload your image with the font you are looking for and it will try to guess what it is. Most of the time it is right on and it is totally free! Of course the better your original image the better the results and I usually crop my image to display just the text. If the system doesn't find a good match you can also post your image to their forum and wait for feedback (I am usually in a rush but have gotten responses pretty quick).

Now I spend less time looking for fonts and more time gardening!

Other similar websites
http://www.identifont.com/
http://www.whatfontis.com/