Epson Photo - Creative Hints and Tips

Print bigger

In this section we’ll show you how to get the best results when you want to print larger photos.

We’ll look at the elements that make up your digital images, the ideal image resolution for printing and what equipment you’ll need.

How big can I print?

There is no real limit to how big your prints can be. They only have to contain enough image detail for good print quality at the selected print size. So how much is enough image detail? To answer this question let’s look at what a digital image is.

Each digital image consists of small square elements called pixels:

A 6 megapixel camera like the Epson R-D1s creates images with 3008 pixels in the horizontal direction and 2008 pixels in the vertical direction, with a file size of 17.2 megabytes.

How can I check the dimensions of my images?

You can check the pixel dimensions of your digital image using an image editing application like Adobe Photoshop Elements. From the Image menu and the Resize selection, you can display the Image Size dialog. The following screenshot shows the pixel dimensions of the sample image above:

The 3008 x 2000 pixels are distributed over the image’s width and height. You can set up different image sizes, but the amount of pixels remains unchanged. That means a bigger image size leads to bigger pixels, a smaller image size leads to smaller pixels. The amount of pixels that are spread over one inch is the image resolution. The more pixels per inch (ppi) an image has, the higher the image resolution. Also the more detailed and sharp your image is, the larger the possible print size. (Pixels per inch (ppi) is often used interchangeably with dots per inch (dpi). We also use dpi for image resolution.)

From high to low resolution

Below are images showing different resolutions. On the lower resolution image you will see the pixels and the image quality decreasing. The image is becoming less sharp and has jagged edges and there is no longer enough image detail.

72 dpi image resolution

180 dpi image resolution

360 dpi image resolution

We recommend you select an image resolution from between 180 dpi and 360 dpi for printing.

A good average is 300 dpi. Save your original master file in 300 dpi and in uncompressed format. Below 180 dpi you loose too much image detail and sharpness. However if you need to print very big, you may be able to use a lower image resolution. Since you usually view a bigger print from a distance, the image will be acceptable.

Remember:

If your resolution is above 360 dpi you won’t actually add image quality to the print. You will only increase the file size and the time to print.

If we set our sample image to 360 dpi image resolution, the biggest size we can print is 21 x 14 cm. At 180 dpi image resolution we can already print a size up to 42 x 28 cm.
3008 pixels x 2000 pixels / 180 dpi = 16 x 11 inches or 42 x 28 cm
3008 pixels x 2000 pixels / 360 dpi = 8 x 5 inches or 21 x 14 cm

Pixel dimension / image resolution in dpi = Print size in inch

Print size in inch 2.54 inch = Print size in cm

The image resolution is directly related to the image width and image height.

If you change any of these three values, you will also change the other two values.

When the Resample Image box is unchecked, the pixel dimensions remain unchanged when you alter the image resolution from 360 dpi to 180 dpi.

Click here for a table showing the relation of camera resolution, image resolution and print size. This provides an overview of the largest image sizes you can print from a digital camera. The print sizes listed in green will print well, in orange the results may be acceptable, but the ones marked in red will not be acceptable.

Edge Smoothing

Epson printer drivers offer the Edge Smoothing feature that improves the print quality of low resolution images by smoothing jagged edges and lines. Using this feature you can get acceptable print results for large prints using a lower image resolution than 180 dpi.

What equipment do I need?

If you want to print a standard photo size, such as 13 x 9 cm at 300 dpi, you need at least a 2 megapixel camera. For an A4 print you would need an 8 megapixel camera. If you print an A4 print at 180 dpi a 3 megapixel camera is good enough.

Table showing print size from pixel dimensions

How to enlarge an image file

If you can’t reach your desired print size even with 180 dpi image resolution, you can add extra resolution with a technique called interpolation. You increase the digital image size or resolution by creating pixels that originally did not exist. The resulting image is larger, but with a reduction of image sharpness. Therefore you should use interpolation within certain limits - until you see a loss of image quality.

With an image editing application like Adobe Photoshop Elements, you can use the Resample Image function with the Bicubic algorithm - this works best with photographic images. When you resample an image from 150 dpi to 300 dpi the image width and height remains the same. It simply adds more pixels to the image width and length.

You cannot expand a compressed file. Therefore keep an uncompressed file as a master file.

Vous ne pouvez pas agrandir un fichier compressé. Par conséquent, vous devez conserver un fichier non compressé comme fichier maître.

What is the right print resolution to use?

Print resolution has nothing to do with image resolution. The print resolution tells you how many dots per inch the printer delivers onto the paper to reproduce the digital image. The optimal print resolution depends on the media you use and the the detail and gradation of your image. On matte paper you can achieve good results at 720 dpi print resolution. On glossy paper you will achieve a better print result using 1440 dpi. If you have smooth tonal gradations like a blue sky or skin tones in your image, you may achieve better results with a resolution higher than 1440 dpi.

720 dpi is the minimum print resolution for photographic images..