Unit conversion between picture pixels inches cm

Today, my friend uses Photoshop to process the picture to save the specified size, but she only to the centimeter to shape the sense, but in the software to save the picture does not have this unit, can only save the units of pixels; Other software can only be saved in inches. I went to the internet to find the next information, finally found the conversion formula, special record:)

72 Megapixels/inch = 28.346 px/cm
300 megapixels/inch = 118.11 px/cm
1 cm = 0.3937 inches
1 inch = 2.54 cm

First of all to tell you a sad news: pixels can not be directly converted into inches, centimeters, to be converted at the DPI!

Two resolution conversions in Photoshop
72 Megapixels/inch = 28.346 px/cm
300 megapixels/inch = 118.11 px/cm
1 cm = 0.3937 inches
1 inch = 2.54 cm
In a common 1024 pixel comparison:

1024 pixels = 3.413 inches = 8.67 cm (300 px/inch dpi per inch ≈0.003333 pixels)

So the 1024 pixel centimeter size is: 1024*0.003333*2.54

1024 pixels = 14.222 inches = 36.12 cm (72 px/inch dpi per inch ≈0.013889 pixels)

So the 1024 pixel centimeter size is: 1024*0.013889*2.54

To lift the resolution, we need to understand the two concepts, image resolution and output resolution, image resolution is the number of pixels per inch, in PPI units, the image resolution is often expressed in each direction of the total pixel count, such as 640x480 pixels, 1280x960 pixels and so on. The image output quality is determined by the output resolution of the image, which describes the number of dots (dpi) that can be generated per inch of the device output image, in dpi, but not always equal.

DPI (dot per inch) output resolution
The printer resolution, also known as the output resolution, refers to the maximum number of points per inch that can be printed in two directions, horizontal and vertical, in the print output, usually in dots per inch or dpi (dot per inch). The so-called maximum resolution refers to the maximum resolution that the printer can print, that is, the limit resolution of the printed output. Usually said the printer resolution generally refers to the maximum resolution of the printer, the current general laser printer resolution is above 600x600dpi.

DPI is the abbreviation for "dot per inch". As the name implies, it refers to the number of points per inch length. In general, we use DPI as the resolution unit for Scanners and printers, and higher values indicate higher resolution. At present, the market for the sale of scanners optical resolution is mainly 600x1200 DPI and 1200x2400 dpi two kinds. The optical resolution of the scanner is composed of two numbers because of the difference in transverse resolution and longitudinal resolution. The smaller number is usually the longitudinal resolution, which is the value we typically use to differentiate the scanner's resolution. That is, the 600x1200 dpi scanner, which we usually simply referred to as the DPI.

The resolution of the computer monitor is about 72dpi, this value is actually calculated: A 15-inch computer monitor For example, the visual area of the horizontal length of about 11.2 inches, if the display mode is 800x600, then the resolution is 800/11.2=71.4. If it is a 17-inch computer monitor, in the display mode of 1024x768, the resolution becomes 1024/12.8=80.

Pixels (Pixel)
For a computer's screen device, a pixel (Pixel) or PX is the most basic unit, a point. All other units are in a fixed proportional conversion relationship with pixels. All length units are based on the display of the screen, and are uniformly converted to the number of pixels before being displayed. Therefore, the relative length and absolute length have no essential difference in terms of the computer's screen. Any unit is actually pixels, the difference is only the proportion of different.

If you extend the discussion to other output devices, such as printers, the basic unit of length may not be pixels, but other units that correspond to the units of measure in your life.

The absolute length of the CSS unit is for output devices. For PT, this is a very common font unit in the Typography tool (Word,adobe, etc.), regardless of whether your display resolution is 1024x768 or 800*600, the same document is printed on paper as a result.

Which length unit is better for writing web pages, px or PT?

I personally prefer PX, because PX can accurately represent the position and size of the elements on the screen, the Web page is mainly for the screen display, not for the sake of printing and other needs.

CSS relative length units (relative length unit)

The relative two words in the relative length unit of CSS indicate that the unit of length will change with its reference value, not fixed.

The following is a list of CSS relative length units:

CSS relative length units
Description

The font height of the EM element the the element ' s font

The height of the "x" of the letter x of the EX

px pixels pixels

% percent percentage

CSS Absolute length units (absolute length unit)

The absolute length unit is a fixed value. For example, we used to have mm, is the meaning of millimeters.

The following is a list of CSS absolute length units:

CSS Absolute Length units
Description

in inch inches (1 inch = 2.54 cm)

CM cm centimeters

mm mm millimeters

PT Point points (1 points = 1/72 inches)

PC Pickup Picas (1 pickup = 12 points)

Pixels are relative to the display screen resolution. For example, the resolution used by Windows users is typically 96 pixels per inch. The resolution used by Mac users is typically 72 pixels per inch.

Unit conversion between picture pixels inches cm