Mona Lisa bitmap example


Grabbing something off of the internet and using it as your art …not always the best plan. Allow me to explain why, because it may not be what you think. You might be thinking of copyrights, licenses and that kind of legal jargon talk that you don’t want to hear. Naw, we’ll save that for another day. It is important don’t get me wrong. You and I and especially I don’t want the kind of problems that copyright infringement could bring. What I’m getting at is how to set up your artwork correctly for a screen printer to use effectively to get the results you want to see!

So back to the first statement; grabbing something off of the internet. Let’s assume it’s legal. Ha ha.

Firstly you should have a simple understanding of bitmap images. Which is what those JPEGs, PNGs, BMPs, and TIFF files are. Bitmap. So if you can zoom in you’ll see that they’re pixels. And then there is such a thing as Hi-resolution and Low-resolution. Grabbing something off of the internet basically results in a Low-resolution file. So then you take a file that has 72 pixels per inch and blow it up to 11-15 inches and you’re hoping it’s going to look good. BRRRRHK. Sorry Charlie, that file that was 72 pixels per inch and two inches wide is Low-resolution… When you blow it up it’ll be blurry. What you need is a file that is 300 pixels per inch or 300ppi (not dpi.. which is a misnomer brought over from the offset printing world) Old school stuff. If your image equates to 30 or 40 inches wide and is 72 pixels per inch you do have a Hi-resolution image. Since it’s a big file to start with you can (if using Photoshop and other bitmap programs) link the sizing format together, change the 72ppi to 300ppi, and maintain the resolution of the image bringing the dimensions of the image down to ..say 12″ and have a ppi (pixels per inch) of 300. Now you have the resolution needed for printing a nice full front on a T-shirt.

When it comes to using bitmap files in a screen printing project, there are a few key considerations to keep in mind. Here’s some information to help you understand how bitmap files are utilized in screen printing:

1. **Understanding Bitmap Files:** Bitmap (or raster) files are composed of a grid of individual pixels, where each pixel contains information about its color and position. Common bitmap file formats include JPEG, PNG, BMP, and TIFF. Bitmap images are resolution-dependent, meaning they can become pixelated or lose quality if enlarged beyond their original size.



2. **Artwork Creation:** To create artwork for screen printing, you can use graphic design software such as Adobe Photoshop, GIMP, or CorelDRAW. When designing the artwork, it’s crucial to consider the final print size, resolution, and color mode.

3. **Resolution and Size:** Screen printing requires artwork with a high enough resolution to ensure quality prints. For most screen printing projects, a resolution of 300 pixels per inch (PPI) is recommended. Higher resolutions may be necessary for detailed or complex designs. Additionally, consider the physical dimensions of your print and ensure that the bitmap file is appropriately sized for the desired output.

4. **Color Mode:** Screen printing typically uses spot colors or a limited color palette, often referred to as “spot color separation.” The colors are typically defined using the Pantone Matching System (PMS), which provides standardized color codes. When working with bitmap files, it’s important to convert the color mode to the appropriate spot color system used by your printer.

5. **Halftone Conversion:** Bitmap images are continuous-tone, meaning they have varying shades of colors. However, screen printing can only reproduce solid colors. To achieve the illusion of continuous tones, a halftone conversion process is employed. This process converts the bitmap image into a pattern of tiny dots of varying sizes, allowing different shades to be reproduced using different densities of ink.

6. **Preparing the Bitmap File:** Before sending the artwork for screen printing, you need to ensure that the bitmap file is properly prepared. This involves converting the image to the appropriate color mode, adjusting the resolution, and converting it into a suitable file format preferred by your printer (such as TIFF or PSD).

7. **Consulting with a Printer:** It’s highly recommended to consult with your chosen screen printer early in the process. They can provide specific guidelines and requirements for preparing bitmap files that align with their printing techniques and equipment.

Remember, each screen printer may have slightly different specifications or preferences, so it’s crucial to communicate and collaborate closely with your printer to achieve the best possible results for your screen printing project.