How to choose best image size for printing

Content

• What size to choose for printing
• Best size of image to print (4x6, 8x10, 16x20, 24x36, and 30x40 inches) or something else?
  • How the print will be viewed?
  • Aesthetic Considerations
  • Viewing distance
• How to calculate Angles of view
  • Horizontal Angle of View
  • Vertical Angle of View
  • Diagonal Angle of View
• What is the optimal distance to observe 4x6 inches image?
• Optimal image width calculation
• Image Size Calculator
• What resolution the image should have to be printed with definite size
• Understanding Print Resolution in Inkjet Printers
• What to do if your photo camera sensor resolution doesn’t allow to shoot images that big enough?
• Choosing the Right File Transfer Methods for Print-Quality Images

What size to choose for printing

The question of what size to choose for printing is very common. There are several typical answers for that question: "the bigger - the better", "the image size should match with furniture size", etc. In this article, we will consider several important aspects of choosing a printing format. We also provide the online Image Size Calculator to determine the optimal printing size based on the viewing distance, the focal length of the lens used to capture the image, and the photo camera sensor size. These parameters are crucial considerations when deciding to print an image.

When photographers are talking about best photography size for printing they usually mean two things:

• What is the best size of image to print (4x6, 8x10, 16x20, 24x36, and 30x40 inches) or something else?
• What resolution the image should be printed with that size?

Both questions are important and should be considered. Let’s start from the size of image you want to print.

Best size of image to print (4x6, 8x10, 16x20, 24x36, and 30x40 inches or something else)

How the print will be viewed?

To choose the right size for printing we need to understand how do we expected people to watch that image: will they take it in hands for a closer look, or will see it from distance, on the wall in the leaving room or in the gallery. So we need to understand what viewing distance do we expect, and understand that viewing distance is actually one of the most important notion when we are talking about printing.

Indeed, if a photographer prints a small image and plans to place it on the wall, it's likely that no one will be able to see what is in that image. Similarly, if an image intended for close viewing is printed too large, it will be difficult to handle and maintain. Moreover, if an image meant to be displayed on a wall is printed excessively large and placed in a small room, it will disrupt the harmony of the space.

In general, if you print the image in a small format, it is easy. You don’t have a lot of paper size option , and resolution of any modern smartphone or photo-camera should be enough. However, the viewing distance is also important here and it closely correlate with the focal lens that you use.

If you are going to put your image to the wall it becomes more complicated. The viewing distance and focal distance of the used lens play here the crucial role. Plus the only situation when image has a lot of free space around is at an exhibition, for all other cases we see images near something else in the room, like furniture and decor elements, so we need to consider the space around.

Aesthetic Considerations

It’s important to maintain a harmonious proportion between the print and its surroundings to enhance aesthetic appeal and ensure the photograph does not overwhelm the space.

One larger print on a vast wall can serve as a focal point, while smaller prints might be more suitable for intimate spaces. The print size should be proportional to the furniture and other elements in the room. A good rule for the print is to be about two-thirds to three-quarters the width of the furniture it is hanging above.

Multiple Prints At times, arranging a series of smaller prints in a grid or gallery wall style can create a significant visual impact and offer more flexibility than a single large print.

The aesthetic impact of a print is influenced by its size, framing, and the space it occupies. Different sizes can dramatically alter the viewer's perception and interaction with the image. For instance, larger prints can make a bold statement and are ideal for showcasing landscapes or dynamic scenes, while smaller prints are often better suited for detailed or intimate portraits. Additionally, the choice of frame can complement or detract from the image. A minimalist frame might enhance a modern print, whereas a more ornate frame could better suit a classical portrait. This section should also address the influence of matting and the type of glass used, which can affect the visibility of details and colors in the photograph.

Viewing distance

Now let’s consider viewing distance more carefully. Traditionally the vast majority of photographers use the next approach for the most common paper sizes:

• 4x6 inches:
  • Optimal Viewing Distance: 1-2 feet (0.3-0.6 meters)
  • Use Case: Ideal for personal photos, desk displays, or small spaces where viewers will be close to the image.
• 8x10 inches:
  • Optimal Viewing Distance: 1.5-3 feet (0.5-1 meter)
  • Use Case: Suitable for small wall spaces, bookshelves, or small gallery setups.
• 16x20 inches:
  • Optimal Viewing Distance: 2-4 feet (0.6-1.2 meters)
  • Use Case: Great for larger wall spaces, living rooms, or as part of a gallery wall with multiple images.
• 24x36 inches:
  • Optimal Viewing Distance: 4-6 feet (1.2-1.8 meters)
  • Use Case: Works well as a statement piece in living rooms, dining rooms, or hallways where it can be viewed from a moderate distance.
• 30x40 inches:
  • Optimal Viewing Distance: 5-8 feet (1.5-2.4 meters)
  • Use Case: Ideal for large wall spaces, creating a focal point in a room, or in areas where viewers can step back and appreciate the full image.

This approach is simple and straightforward. Is it give good results? - Sometimes. Let’s consider why and how to get better results.

Usually when we look at the image on the wall or in our hands it has some distance from our eyes and it also has some angle size, that depends on that distance. For example we can take the small 4x6 inches image and watch it from distance – it will appear as small, we move it closes it becomes bigger, more close – it becomes huge. It happens because the distance was changed and the angle size was changed too. It works exactly as a lens on the photo camera. If mountain is far from photographer he can use the lens with a long focal length (with small angle of view), but if the mountain is closer, photographer should take the short focal length lens (with wide angle of view). Let’s say photographer used 50 mm lens, to take the image, it means, if he has full frame sensor:

• horizontal angle of view = 39.6 degrees
• vertical angle of view = 27 degrees
• diagonal angle of view = 46.8 degrees

It means that if photographer wants the viewer to have the strongest impression from the image, the distance from the viewer to the picture and the sizes of the picture should provide same or close view angle. Therefore we can talk about the optimal distance to observe printed images. It depends on their sizes and the lens that were used to take a picture.

Let's illustrate it, see image below.
On the first photography the wide angle lens with broad angle of view θ was used. Here the viewing distances D₁ and D₂, and image sizes W - width and h - height.
On the second photography the lens with longer focal distance was used.
We can see that the first and second image have the same sizes W and h, but the viewing distances D₁ and D₂ longer for the second image. It happends because of the smaller angle of view θ, and it means that the image that was taken with a lens with longer focal length might be comfortably observerd from the longer distance.
Otherwise, if we have the same viewing distance, let's say 5 feet, the image that was taken with lens that has smaller angle of view θ, might be printed smaller than the image that was taken with wide angle lens. Let's consider it in more details below.

How to calculate Angles of view

To calculate the angle of view for a 50mm lens on a full-frame camera, you can use the following formula based on the lens focal length and the sensor size:

angle of view = 2 * arctan(d / (2 * f))

Where:

• d - is the sensor dimension (width or height, depending on whether you want the horizontal or vertical angle of view).
• f - is the focal length of the lens.

Horizontal Angle of View

For the horizontal angle:

angle of view_horizontal = 2 * arctan(36mm / (2 * 50mm)) ≈ 0.346 radians * 180 / π ≈ 39.6 degrees

Vertical Angle of View

For the vertical angle:

angle of view_vertical = 2 * arctan(24mm / (2 * 50mm)) ≈ 0.236 radians * 180 / π ≈ 27 degrees

Diagonal Angle of View

Here, on the first step we need to calculate the length of diagonal:

Diagonal = √ (36mm² + 24mm²) = 43.26mm

angle of view_diagonal = 2 * arctan(43.26mm / (2 * 50mm)) ≈ 0.408 radians * 180 / π ≈ 46.8 degrees

What is the optimal distance to observe 4x6 inches image?

Now let’s solve the opposite task, let’s say we have an image, for example 4x6 inches, let’s say it was taken from 50mm lens. Can we estimate what distance will be optimal for observing this image? Let’s try to do it.

The first step here is to calculate the angle of view for the 50mm lens, and we already did it on the previous step: horizontal angle of view = 39.6 degrees (or 0.346radians).

Let’s go to the next step and calculate the distance. To make the 4x6 inch image subtend the same angle, we use the formula:

Distance = W / (2 * tan(θ / 2))

where:

• W - is the width of the image in the same units as D (we'll convert 6 inches to meters for consistency), it’s 0.1524 meters.
• θ - is the horizontal angle of view calculated previously (in radians), it’s 0.459 readians.

Now let’s calculate the distance:

Distance = 0.1524 meters / (2 * tan(0.691 redians / 2)) ≈ 0.212 meters ≈ 8 inches

From this calculation we can see that this 8 inches is smaller than a usual 12 – 20 inches distance that we use for observing 4x6 inches image from our hands. Yes, 4x6 inches size is very convenient to keep image in the pocket, but it is too small to observe it comfortably.

It is interesting that some photographers, who print small images, believe these images appear more three-dimensional when viewed through a magnifying glass. This effect arises because the magnifying glass enables viewing from an optimal, closer distance—unachievable with the naked eye at 8 inches—thereby enhancing the perceived depth and volume of the image

If we print the same image with size 8x10 inches, the optimal viewing distance will be around 14-17 inches and it will be much more comfortable to observe it. Let’s go forward and calculate optimal image width based on the distance and lens that we have.

Optimal image width calculation

To calculate the image width we simply transform previous formula:

image_width = 2 * Distance * tan(θ / 2)

Let’s imagine that we are going to observe the image from 5 feet distance, (it’s 1.52 meters)

image_width = 2 * 1.52 meters * tan(0.691radians / 2) ≈ 1.094 meters ≈ 43 inches

We can use the same formula to calculate image height (with 0.236radians respectively) and get vertical size = 29 inches.

Step-by-step algorithm to choose the optimal image side is:

• To choose the wall where you want to place he image
• Consider the point where people will usually see the image
• Calculate the sizes of image based on that distance and focal length that was used to take the image.
• Compare the size you get with furniture and other elements of the room (image shouldn’t be too big or small), if you see that it isn’t in harmony with other part of the room you can consider another image.
• Please remember that the optimum size of an image is just a recommendation, based on the idea that the image the viewer observes should represent the same field of view that the photographer saw through the lens. You shouldn’t follow this rule too strictly. Often, the real image is bigger or smaller than the optimal size, and it still looks perfect.

Of course it isn’t so convenient to use all that formulas every time when we need to print image so you can use optimal image size calculator below.

To ensure that the styles of the image size calculator do not affect other input fields on the HTML page, we can use more specific CSS selectors targeting only the elements within the calculator's form. One effective way to do this is by using the form's id as a prefix for the CSS selectors. Here is the modified HTML and CSS: Modified HTML: html

Image Size Calculator

What resolution the image should have to be printed with definite size

Now, once the photographer has decided on the geometric sizes the printed image should have, it becomes possible to evaluate the digital image quality and determine whether there is sufficient resolution for printing at that size. To do this, we need to understand what print resolution entails.

Understanding Print Resolution in Inkjet Printers

Print resolution in inkjet printers is defined by the number of ink droplets a printer can deposit on one square inch of paper. This crucial measurement directly influences the image quality and visual details of your printed materials. Inkjet printers operate by ejecting tiny droplets of ink onto the paper to create an image. The term "dots per inch" (DPI) is often used to describe this process, reflecting the density of ink dots. A higher DPI means more dots are packed into a square inch, which generally leads to sharper images and richer colors.

Modern inkjet printers vary widely in their DPI capabilities. Consumer-grade models typically range from 600 to 1200 DPI, which is adequate for everyday printing tasks. However, professional-grade inkjet printers can offer much higher resolutions, some going up to 4800 DPI or more. These high-resolution printers are especially suited for professional photographers, designers, and anyone who needs the highest quality prints.

For digital image resolution we usually consider “pixels per inch” (PPI). When it comes to printing digital images, Pixels Per Inch (PPI) directly translates into Dots Per Inch (DPI). Essentially, each pixel in your digital file instructs the printer on how many dots of ink to deposit on the paper. This relationship means that one pixel typically corresponds to one dot of ink.

Let’s consider 4x6 inches image. How many dots per inch (DPI) it should have to be printed with acceptable quality? The minimal number of DPI that provide acceptable quality is 300 dots per inch, any modern printer can do it.
As PPI converted directly to DPI, image size should be:

4*300 x 6*300 = 1200 x 1800 PPI

This is a minimal size for printing 4x6 inches image.

What about the 20x14 inches size we calculated earlier?

20*300 x 14*300 = 6000 x 4200 PPI

It means you need at least 6000*4200 = 25.2 megapixels to print the image this size with DPI 300

Can we print a 1200x1800 pixel image at a size of 20x14 inches?
Let’s calculate:

1800 / 20 = 90DPI and 1200 / 14 = 85DPI

It is 3 times less than standard 300DPI you still can print it, but it dramatically affects the resolution of the print and we don’t recommend to print photography with such a quality.

Let’s say you have a photo camera with 36MP sensor that allows you to shoot 7376x4932 size image, the maximum size you can print with 300DPI is:

7376 / 300 x 4932 /300 = 24.5x16.4 inches

You can use this approach to calculate the maximum image size for your smartphone camera, or photo camera and use it when placing the printing orders.

You can print the same 36MP image on 4x6 inches paper as well. Generally, printing a large image on a smaller paper size poses no issues. Otherwise if you want to print a large photo, you might be limited by the camera's resolution. Without adequate resolution, you cannot achieve a large format print.

What to do if your photo camera sensor resolution doesn’t allow to shoot images that big enough?

Let’s consider how it works. We started from viewing distance and the focal length, and here are two possible solutions:

• The first one is the viewing distance, you can consider another place with shorter viewing distance for this particular image. The smaller viewing distance means the smaller print size in inches you need for the same optimal point of view. So, probably you can place image to another wall.
• The second solution is to use longer focal length lenses, for example you can use 70mm lens instead of 50mm. If you use longer focal length – the angle size of your image is smaller and it means the smaller print size.

Some people recommend to play with margins or do collages but it isn’t really affect the viewing distance. The image with broad margins will take more place on the wall and it might helps if you need to do it to balance image size with furniture size. But if the image is much smaller than necessary, it won’t createimpression wanted from the long distance, disregarding what margins will it have. The same situation with collages. Yes, several images will take more place on the wall and probably will be more balanced with furniture and other stuff in the room, but it will not change the view point.

Choosing the Right File Transfer Methods for Print-Quality Images

When preparing images for printing, the method of file storing and transfer is crucial to maintaining image quality. Similar to how an image loses clarity when converted to a screenshot, it can also degrade through inappropriate sharing methods. Many popular communication platforms like Slack, Teams, Facebook Messenger, Instagram, and Twitter typically compress images during transfer, reducing the resolution and quality of the original file.

For optimal preservation of image quality, it is advisable to use platforms specifically designed for photo sharing, that maintain the integrity of your files, and avoiding the compression. One of the best way to keep images is simple external hard drive, it is relatively cheap now and allow a photographer to keep high resolution images with no compression. If you use this approach – you need to remember about backups.

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