What is the difference between dots and pixels?

[Panama Hat & Camera]

In cameras, the viewfinder resolution and the display resolution are usually expressed in dots, but sensor resolution is expressed in pixels.
In that case, what is the difference between dots and pixels?
Cheers,
Antonio.

[dje]

For LCD screens, the term dot is possibly used instead of pixel because each dot consists of 3 sub-pixels (r g and b). However television screen resolution is often referenced by pixels. Take your pick!

Dave

[pnodrog]

For LCD screens, the term dot is possibly used instead of pixel because each dot consists of 3 sub-pixels (r g and b). However television screen resolution is often referenced by pixels. Take your pick!

Dave

Don't confuse me even more. I'm still trying to come to terms with the practical difference between ml and cc.....

[xpatUSA]

For LCD screens, the term dot is possibly used instead of pixel because each dot consists of 3 sub-pixels (r g and b). However television screen resolution is often referenced by pixels. Take your pick!

Dave

For camera screens, marketing has dictated that the 'dots' are actually sub-pixels. Therefore, a 912,600 dot screen is actually the good ole' VGA as in 640x480 pixels. Each color is framed in sequence r - g - b which is why LCDs and EVFs have a bit of a flicker in the presence of motion.

Sensor color resolution varies depending on the construction e.g. type of CFA, no CFA, Foveon, etc.

[dje]

For camera screens, marketing has dictated the dots are actually sub-pixels. Therefore, a 912,600 dot screen is actually the good ole' VGA as in 640x480px. Each color is framed in sequence r - g - b which is why LCDs and EVFs have a bit of a flicker in the presence of motion.

For LCD computer monitors each pixel is also made of 3 sub-pixels but the description is for example 1920x1080px and never referred to by "dot" quantity.

.

Thanks for the enlightenment Ted. There’s your answer Antonio!

Dave

[DanK]

I don't know that a history is all that helpful in sorting out currently inconsistent uses.

Keeping the terminology of pixels and subpixels, I think this is current usage. Correct me if I'm wrong.

1. When you set print resolution, "dots" are pixels. For example, you'll often see statements like "the native resolution of Epson printers is 360 dpi." If you look in Lightroom, that exact setting is labeled ppi.

2. However, when looking at printer specs, you'll often see "dots" used to refer to neigher pixels nor subpixels, but rather to ink droplets. For example, the specs for my printer show a maximum of 2400 "dpi". Closer reading shows that this is the number of ink droplets per inch. Given that the print head has over 18,000 nozzles (1,536 Nozzles x 12 Inks), it can lay down a lot of droplets per pixel.

3. dpi is irrelevant in most cases when exporting electronic files, which have no dimensions, hence no "per inch".

[pschlute]

dpi is irrelevant in most cases when exporting electronic files, which have no dimensions, hence no "per inch".

I would say in ALL cases

[xpatUSA]

I don't know that a history is all that helpful in sorting out currently inconsistent uses.

Post that had that link duly deleted. I wouldn't want to be unhelpful ...

Keeping the terminology of pixels and subpixels, I think this is current usage. Correct me if I'm wrong.

You are not wrong, as far as I know. People do use "pixels" and even "subpixels" and "dots". What people mean by them is, of course, moot. As opposed to "pels" which haven't much of lately ...

1. When you set print resolution, "dots" are pixels. For example, you'll often see statements like "the native resolution of Epson printers is 360 dpi." If you look in Lightroom, that exact setting is labeled ppi.

2. However, when looking at printer specs, you'll often see "dots" used to refer to neigher pixels nor subpixels, but rather to ink droplets. For example, the specs for my printer show a maximum of 2400 "dpi". Closer reading shows that this is the number of ink droplets per inch. Given that the print head has over 18,000 nozzles (1,536 Nozzles x 12 Inks), it can lay down a lot of droplets per pixel.

3. dpi is irrelevant in most cases when exporting electronic files, which have no dimensions, hence no "per inch".

Antonio was asking about cameras, so going on at length about printers might be blurring the initial question a bit.

[Acorn]

I best understand the difference between dots and pixels having once worked in the commercial printing and process engraving world – letterpress, offset-litho etc.

Dots are essentially a unit of measurement per linear inch - dpi. The deciding factor comes down to the actual paper surface the commercial printer is working with. Most will remember the days of letterpress-produced newspapers and actually being able to see clearly the dots in reproduced photographs (half-tones) because of the paper quality. These were typically in the range 65-85 dpi.

High quality coated papers used in glossy promotional material, e.g. leaflets, magazines or books, allow the commercial printer to use half-tone blocks with much higher dpi’s typically ranging from 120 to 150 dpi or even greater.

In all cases the dots were achieved by placing what is known as a screen in the process camera between the illuminated object (photograph) and the sensitive photographic film held in a dark-slide. The reproduction of colour pictures from transparencies or prints to produce four-colour blocks or lithographic plates (CMYK), involved precisely angling the screen and using colour filters. Angling the half-tone screen prevents the four colours printing directly on top of one another.

Present-day sophisticated desktop publishing software allows the operator to automatically select either CMYK output for commercial printing or RGB for photographic printing, the latter interpreting the RGB pixel make-up of the photographic image.

This is a lengthy posting but I hope it goes some way to help.

[pnodrog]

It's just like a glass half empty or a glass half full in that the half value doesn't change and the rest depends on who you are or what you are doing....

[pnodrog]

I would say in ALL cases

Not in all cases.

When doing desktop publishing, graphics design or CAD there are times when it is very important to have the image displayed either at actual size on your monitor or at a known scale. To do this the software must know the DPI/PPI of the image file being displayed and the pixel pitch of the display screen.

So in a 100% view an a4 page will appear at a4 size on the screen. Having a brochure, business card or wedding invitation etc displayed on the monitor at the actual size helps in making sure the fonts used and their sizes are appropriate.

[Manfred M]

Absolutely agree Paul - when I work on an image I am planning to print, I work at 100% resolution for things like sharpening. The ensures that I am not seeing any interpolation by the tool I am using to get the most accurate view of what I am working on. In that case I will ensure that my image ppi is the same as my printer's native dpi.

[pschlute]

I have always assumed that ppi is a property of the image, and that dpi is a property of the printer What am I missing ?

[xpatUSA]

I have always assumed that ppi is a property of the image, and that dpi is a property of the printer What am I missing ?

Unfortunately, Peter, those two terms are used interchangeably in the genre, according to many references on the internet.

That usage causes endless confusion in these fora, not unlike "resolution" or "exposure" for example.

[Manfred M]

I have always assumed that ppi is a property of the image, and that dpi is a property of the printer What am I missing ?

ppi is little more than a scaling factor that is somewhat useless given that our screen drivers take care of scaling for us. The old CRT screens, I believe were all set to 72ppi, regardless of screen size.

The only thing we really need to think about with dpi is that the native resolution for printers is fixed. The only time I really care about this is when I prep an image for print and convert it to the right size, based on the printer resolution. Some claim that the printer drivers are so good that there is no noticeable issue is one is off a bit. I really don't know, but suspect that native resolution should be the cleanest way to go.

[pschlute]

What is the relationship between pixels and dots when it comes to printing?

Does one dot equal one pixel ?

[Manfred M]

What is the relationship between pixels and dots when it comes to printing?

Does one dot equal one pixel ?

Only when the image is scaled to full print size and the ppi is set to the native resolution of the printer (300 dpi for Canon and the large photo guality HP printers and 360 dpi for Epson printers).