My print isn’t as colorful as it is on my screen: RGB vs CMYK

My print isn’t as colorful as it is on my screen: RGB vs CMYK
By: Luis Martinez

A client concern that we’ve come across in past has been “Why does this colorful image look so bad printed out? Can’t it look like it does on my monitor?” The simple answer is no. This is because the color presented to you on your monitor is using light, whereas the color you’re seeing on a page uses colorants. Think ink or paint.

RGB: Additive color

When you view a monitor, the colors you see are Red, Green and Blue, the primary colors of light. When added together equally, you get white. Turn off all lights, and you get black. Monitors still show you light mixes, but it’s done optically by having the red, green and blue lights so close together.

Things to note:
• Color vibrancy is seen through your eyes viewing illuminated colored lights being “added” together
• Mix two RGB colors together and you’ll get cyan(G+B), magenta(R+B) and yellow(R+G)

CMYK: Subtractive color

Cyan, magenta and yellow are the primary colors when dealing with ink on paper. Add these together equally, you’ll get a grey. Lay no color down, and you get white. Because grey is the darkest color you can achieve, black is introduced. In printing this is your key plate that gets ran first. Hence, the “K” for key.

Things to note:

• When you see cyan ink on paper, it’s stopping your eyes from seeing green and blue light. Essentially, “subtracting” light.
• Unless youre adding more plates, a Pantone neon green for example, you won’t be able to get close to what a colored light can produce.
• Red, Yellow and Blue were primary colors before color theories were developed. Think of the only three crayons you needed in kindergarden.

Conclusion:

Keeping images in RGB format is the best thing you can do to retain color vibrancy on your monitors, cell phones, etc. You will see bright green and neon blues.  If you decide to print an image, work colorful sections yourself in CMYK. Don’t let a computer decide your blue sky, that can’t be reproduced, should just be a dirty purple.

Megapixels and Size

WHAT IS A MEGAPIXEL?

A pixel, px, is a single square of color that composes a digital image. A megapixel, MP, is one million pixels. When dealing with images, your end usage will determine the megapixel requirement of the camera that’s capturing it.

As of this writing, the average $100 point-and-shoot camera is 10MP. Professional SLR cameras costing $500-$5000 on average gets you 10-20 MP. I won’t go into the cost of our 33 MP Leaf Aptus 75 camera back.  These are just estimates and costs of cameras vary on features that would have to be covered in a different article.

Printing uses the term dpi, or dots-per-inch, which is the physical equivalent of pixels-per-inch for simplicity’s sake. The average hi-res print is run at 300dpi, while your computer’s monitor displays at 96 ppi on average.

MY IMAGE IS GOING TO PRINT

I found that most sites give you a print size at the end of a chart based on a megapixels or resolution. I feel it’s more appropriate to show the numbers based on your end usage/size first.

Key:

Print Size (at 300dpi); Resolution; Minimum Megapixel Camera

4″x6″ print; 1200px X 1800px; 2.2MP

5″x7″ print; 1500px X 2100px; 3.2MP

8″x10″ print; 2400px X 3000px; 7.2MP

11″x14″ print; 3300px X 4200px; 13.9MP

16″x20″ print; 4800px X 6000px; 28.8MP

These are the numbers for optimal image quality. You can always trade size for resolution, essentially making it “blurrier” the larger you scale it up. Also, image quality is affected by the camera’s settings, sensors, etc.

MY IMAGE IS GOING ON THE WEB

This is the medium where you don’t need a lot of horsepower capturing an image. Your saving grace is that most websites are no larger than 1000 px wide.  That means any point-and-shoot camera would have the resolution for use on web. You’ll notice some people use a cell phone camera that’s 1-3 MP when quality is not of the essence.

FINAL THOUGHTS

There are many ways you can make an image look bad. In order to get the best quality image for your end usage, please do not commit these as well as other offenses I’ve seen in the past:

• Scaling up more than 200% and expecting perfect clarity.

• Assuming dark areas in a shot will look good when you make it lighter in Photoshop and vice-versa.

• Supplying a hi-res image only to use a 1″ x 1″ crop of it to be scaled up for printing a large size.

• Supplying a jpeg to a retoucher when you have a .RAW, .CR2 or .NEF on hand.