It is difficult to focus on an uncalibrated monitor, since the similarity of the print to the monitor screen will be partial.

There are three options for checking the color profile. The first way to print black and white photographs is that they must be black and white, without color impurities. You need to look after the ink has completely stabilized and with the source for which the color profile was ordered. The second way is to print photos and compare them with a calibrated monitor. It is possible that you will have to compare in paper simulation mode. Photoshop, Illustrator, InDesign, CorelDraw can do this. The third way is to print our test images and visually analyze their quality. The fact is that sometimes the printed image itself has a color shift, especially when shooting indoors. We tried to collect images without obvious color deviations.

Two blocks of images are presented:

• Checking RGB drivers. Printing from Windows using native printer drivers. RGB color profile.
• Checking Photolabs (wet printing). RGB pictures.

COLOR-RICH TEST IMAGES FOR TESTING THE PHOTO LAB (WET PRINTING).

Test photo. Test photo for printing. Test image for printing. Test photo to check the RGB color profile. Image for tests.

IntroductionWhen creating a methodology for testing printers, the main question that arose was whether it was worth making it separate for different types of devices. Under the general name of printers, there are actually hidden devices that are quite different in capabilities and purpose. An attempt to find and apply a universal cure for all diseases does not always lead to success - the patient may die. However, the desire to adhere to some common standards and a unified approach to testing peripheral devices in this category ultimately prevailed, albeit with certain reservations. These, first of all, were restrictions on the types of printers that fall under the scope of this technique. We deliberately extended its effect only to color inkjet and laser printers, without adapting it to matrix and thermal sublimation printers, due to the specificity and low prevalence of such models on the Russian market. In principle, this document can be used as a guide in the future when testing monochrome laser printers, excluding from it the items regulating the determination of color rendering quality.
The methodology we created concerns mainly two most important characteristics of printers, which, of course, are print quality and productivity. Of course, there is a third indicator - the cost of the product, which worries all users, but it is not within the scope of this technique and is dictated by the seller of the product. We can only subjectively assess the correspondence of the price of the printer to its other characteristics we are considering. In addition to this, of course, there are other factors that influence the decision to purchase a particular printer.
Before moving directly to the testing methodology, let's say a few words about other aspects that we will take into account when considering the next model of a printing device. We are talking about the following parameters:

Technical characteristics;
Printing technology;
Design;
Software;
Printer equipment.

There is no point in describing the above points in detail - most users who have more or less to do with printers understand what we are talking about.

Print quality

The “print quality” indicator is general in nature. In fact, it is formed as a result of the interaction of several components, which together make it possible to ultimately obtain a pleasing picture on a sheet of paper. The overall result will depend on printing technology, ink, paper, software and some other factors. Naturally, in our case the task is to control what we get at the output.
One of the main factors that determines a high-quality image is the printer’s ability to provide correct color reproduction. Let’s immediately make a reservation that we are talking specifically about the technical side of this issue, and not about the most beautiful and pleasant-looking image. As a result of its work, the printer must print an image that is as close as possible to the electronic original in three color components (RGB) in each pixel. Here it would be appropriate to recall that, of course, a finished color copy in practice is always worse than the original, since it is almost impossible for a printer to absolutely accurately convey the entire range of colors of the original. In addition, an important element in the operation of any printer is the ability to provide high-quality transmission of halftones. In some cases, the printer’s inability to provide uniform color fill throughout the entire brightness range becomes problematic for performing this task. Usually the most problematic areas are very light-colored areas. In color printing, black is formed by mixing RGB colors, and the final result is not always satisfactory due to the violation of their correct balance. Another aspect of obtaining a high-quality image on paper is the resolution of the printer, which allows for the correct transmission of the smallest details. Many modern printers have a very high print density declared by their manufacturers, which in practice does not always have a direct relationship with the actual physical resolution, and the true state of affairs can only be determined through testing.
Now that we've looked at the problems that arise when trying to achieve maximum print quality, it's time to choose ways to specifically implement the task before us.
The resulting prints are evaluated subjectively and objectively. The first method is based on the traditional visual method, which allows you to identify defects visible to the naked eye. The second method is based on a more accurate and impartial assessment of print quality. It consists in the fact that printed test images are scanned on a reference scanner and converted into digital form. Next, using special software, RGB indicators are taken from special “plates”, and the degree of deviation in color characteristics from the original image is determined. In order to take into account the degree of error in the results introduced by the scanner itself, it is calibrated before testing using a proprietary Kodak Q-60 color target.
The above methods for assessing print quality fully apply to test images of color printing. If you use only black ink for printing, the procedure for testing prints is somewhat simplified due to the fact that there is no need to study color characteristics.

Print speed

All manufacturers indicate the printing speed in the documentation for their printers. The data given in the specifications refers to various operating modes and is expressed in the number of pages printed per minute. However, not everything is so simple. In theory, if manufacturing companies have a unified approach to determining speed for all models, the numbers should be quite correct, but as you might guess, there is no certainty that when determining print speed, all companies use the same reference documents. . In order to compare printers from different companies in terms of printing speed, it is better to conduct your own testing. In such a case, we use the same templates to determine the performance of all models, regardless of their affiliation with a particular company, and we will be able to make a reasonable comparison between them on this indicator.
To determine the printing speed, we will use three pre-prepared electronic layouts displayed on A4 sheets. The first of the templates is one page of text. The second layout consists of a combination of text and color graphics. In the first two cases, standard office paper (80 g/m^2) is used for printing. As the third layout, we use a color test image prepared by us, printed on the best quality photo paper recommended by the manufacturer. In this case, the print mode is selected with the highest possible density. The printing time in all cases is recorded from the moment the Print command is issued until the sheet comes out into the tray.

Basic tests

The list of basic tests includes those that subsequently make it possible to compare the quality and speed of printing of any printer models when they perform the most characteristic functions. To make it easier to compare final results for A3 and A4 printers, the same paper size is used. List of main tests:

1. Test for quality (speed) of color printing (office and photo paper A4). The file used is TF1 (description of the files used below).
2. Monochrome print quality test (A4 office paper). The file used is TF3.
3. Monochrome printing speed test (text, A4 office paper). The file used is TF4.
4. Mixed printing speed test (b&w text/color graphics, A4 office paper). The file used is TF5.
5. Monochrome printing resolution test (A4 office paper). The file used is TF2.
6. Color printing resolution test (A4 photo paper). The file used is TF2.
7. Test for moisture resistance of ink on paper after the print has dried (wet cotton wool).

Additional tests

In addition to the above-mentioned basic tests for print quality and speed, based on studying the ability of printers to perform their main functions, it is possible to conduct additional tests based on the specific capabilities of specific models. The point is that some printers allow you to print on CDs, roll paper, thick media, etc. etc. Additional tests allow you to evaluate the quality of such functions. The feasibility of additional testing will be decided based on the results of studying the characteristics of the printers included in the testing.

Notes on the testing procedure

Now let's talk about how the testing itself is carried out. Before it starts, the printer heads are calibrated. If certain printer models require the installation of an additional cartridge to obtain a photorealistic image, then a similar step is taken. The printing mode is carried out with the “default” settings, in the absence of any comments in the text. The final testing parameters are selected depending on the specific characteristics of the devices under consideration.

Test template files

TF1 file


In order to determine the ability of printers to produce high-quality color printing, a special target was created. It presents several color and one black and white artistic image, serving for a subjective assessment of quality.
In addition, on the target there is a rectangle with a gradient fill of black from 0 to 100 percent, as well as a seven-color plate with “steps” of varying intensities and known RGB values. With their help, you can objectively assess the degree of correctness of color rendering of printers.

TF2 File

This test file in PDF format is intended to determine the resolution of printers. The USAF 1951 test image can be used to determine printer resolution. On this target there are several groups consisting of six elements each. The elements in each group are progressively smaller and numbered from one to six. Each element in the group is represented by two triples of rectangles located vertically and horizontally. Each new group of elements is smaller in size than the previous one. The level of nesting of groups is quite large and allows you to find out the maximum print resolution that the printer is capable of.

TF3 file

Intended for determining the quality of monochrome text printing, a doc-format file consists of several dozen lines of font of various sizes and styles, which also allows you to determine, to some extent, the maximum resolution.

TF4 file

This template is designed to determine the speed of monochrome text printing. A doc-format file contains one page of text written in Times New Roman font size 10 points with a regular style and single line spacing.

TF5 file

In order to determine the printing speed of mixed documents (monochrome text/color graphics), a file in doc format is used. It contains text in 10-point Times New Roman font with regular style and single line spacing and two color images (diagrams).

Assessment of color rendering quality based on objective indicators

When assessing the color rendering quality of a printer, we will to some extent adhere to the principles of the methodological approach described in the article about testing scanners.
The image of the printed target (TF1 file), digitized after scanning in color mode with the optical resolution of the scanner, is used to determine the RGB color components at certain points using special programs, for example, Adobe PhotoShop. To do this, the results are taken on all eleven “sites” of different brightness of seven color “rulers”: Red, Green, Blue, Black, Yellow, Magenta, Cyan.
Next, all received data for each control point from the scanned image is entered into a special table.
Based on the results for all seven colors, the integral coefficient of correctness of the printer’s reproduction of original colors is determined. It is calculated as the sum of the difference, taken modulo, of the color component (RGB) values ​​of each of the control points in the scanned image and the reference file, then divided by seventy-seven.


The smallest value obtained as a result of calculations will be a sign of the most accurate reproduction of the color palette of the original by the printer among those who took part in testing. Note that the indicator we propose is suitable only for a comparative analysis of the quality of color rendition between models and cannot be an absolute assessment.

Color balance and halftone quality

Based on the measured RGB values ​​of a rectangle with a gradient fill in black, a graph is constructed that reflects the quality of the printer’s performance of this procedure. The X axis is the distance expressed in pixels, and the Y axis is the RGB values ​​of the pixels.

The final picture in the case of close to ideal looks approximately the same as can be seen on the graph. The lines from all three black RGB components merge into a single whole, and the absence of dips and peaks indicates their balance. The desired range of color component (RGB) values ​​should be from 0 to 255.

We will consider our methodology a basic document available for modification and development as it is applied in practice.

A large selection of test sheets for testing the print quality of various printing office equipment: from monochrome laser printers to color inkjet photo printers. The set of test sheets is extensive and everyone will find something interesting here - from the most ordinary “Malevichs” to complex color mosaics. The article will also tell you how to identify some printing defects using test sheets.

1. This archive contains 12 sheets for testing monochrome laser printers:

2. Two sheets that were used for the following illustrations:

3. One test sheet to check monochrome printing:

4. One test sheet to check color printing:

5. Test sheet for checking the printing of large and small fonts:

6. Test sheet for checking photo printing:

7. A very successful test sheet for color printing:

8. Actually “Malevich” for checking monochrome laser cartridges and cleaning black inkjet cartridges:

9. Six-color test sheet:

10. Quality test sheet for inkjet photo printers:

11. Three-color test sheet for checking/cleaning color cartridges of inkjet printers:

Now let's move on to practice.

2. Four repeating black dots along the vertical line of the white test sheet. This test sheet characterizes the most common type of defect during printing - a point breakdown of the photolayer of the photodrum. There may be several such breakdowns; they come in different diameters from barely visible tenths of a millimeter to thick dots. There are no technologies for restoring the photolayer, so the only panacea for this problem is to replace the entire photodrum. Although it should be especially noted that this decision depends on the client’s requirements for print quality. When printing only text, small pinholes are practically indistinguishable and the photoconductor does not need to be changed for now. Over time, the dots become bolder, and then you can think about replacing this element. Small white dots or stripes are usually visible on a black test sheet, but for this defect a white sheet is more indicative.

4. A solid black vertical stripe or several stripes on a white test sheet. It can be intermittent as in the example, usually appearing at the edges. This means that the photolayer on the drum is seriously damaged; experts call such photodrums burnt. These damages are easy to see with the naked eye. At the site of damage, the photolayer is either absent, exposing subsequent layers, or has a characteristic brown tint. The image drum of the cartridge must be replaced. In this case, there are no other options for improving print quality. On a black test sheet, a broken stripe is usually visible along the very edge.

Classmates

When in inkjet printer Ink runs out, the user needs to refill the cartridge or purchase a new print cassette. Some users purchase only original consumables, others prefer compatible inks, but both the former and the latter are interested in obtaining high-quality prints and extending the life of their printing equipment.

Unfortunately, it is impossible to check the quality of ink in a store, so the user has to rely only on the integrity of the manufacturers and personal experience in choosing consumables. But testing the quality of purchased ink at home is not difficult. To do this, you will need a printer, high-quality paper, and, in fact, purchased ink. The essence of testing inkjet inks at home is to print out specific test pages or test tasks and carefully analyze them in order to identify the advantages and disadvantages of this ink. Test page to check the quality of inkjet ink can be found on the Internet.

Test page elements for testing inkjet ink quality

If you plan to use the ink for printing home photos, then the first two elements of the test page will be enough for you, but if you are using the ink for professional commercial photo printing, then the test page should contain all the elements listed in the figure above.

An example of a test page with the designation of its main elements is presented below.

Legend:

1, 1a – gradient transition from white to black; 2 – portrait of a person with a natural skin tone;

3 – image fragments containing light elements on a dark background and vice versa;

4 – dies filled with different colors.

A sample test page with the designation of its elements

When examining the resulting test page, you should pay attention not to the exact match of the shades of the resulting image with the original, but to the balance of the selected ink set. The main criterion here is the gray fill that the inkjet printer generates during printing. The gray color must be pure, without any foreign tint. If such a shade is present on the print, then the selected ink is far from ideal.

An example of color distortion when printing in gray is shown in the following figure. Here is a comparison of several scans obtained when testing inkjet inks. The same printer was used in testing, the same settings were set when printing, and printing was done on the same paper.

Ink A

Ink B

Ink B

Scans obtained from inkjet ink testing

Ink B And IN when printing they form foreign shades: on the print B– blue, on print IN– lilac. This is especially noticeable in the gray shading of the picture located in the lower right corner. Ink A demonstrated accurate color reproduction, which indicates their quality and balance.

An extraneous tint may appear both on the entire image and in its individual areas. Also, poor ink quality may be indicated by excessive paleness of the print, distortion or mixing of colors, insufficient image clarity and poor rendering of small details. Only ink cartridges can be to blame for the appearance of the listed symptoms. Most likely, the manufacturer did not test their ink sufficiently and released it to the market ahead of time. Pay attention to the fine details in the darkest and lightest areas of the image. Good printer ink renders fine details better than bad ones. As an example, consider two scans of photographs printed with different inks on the same inkjet printer using the same paper.

Ink A

Ink B

Photos printed using the same photo paper

on the same inkjet printer, but with different inks

Ink A demonstrate more realistic color rendition and better depict the smallest details of the image. Ink B They do not convey halftones and small details clearly enough, their colors are not as natural and deep as on the first print. Light halftones in the picture B look garish, there is no smooth transition between light and dark areas of the image.

If you get insufficient quality test prints and are about to run to the supplies store for new ink, stop! Practice shows that you can achieve quite satisfactory print quality by experimenting with the settings in the “printer-ink-paper” system. If you do everything correctly, you can increase the realism and colorfulness of your photos and improve the color rendition of midtones and shades. If you plan to use inkjet ink for professional photo printing, then you will have to spend a little more time finding a balance in the printer-ink-paper system. You may need to print more than one test page before you are satisfied with the image. As an example, consider the figure.

Basic test page

The basic test page has a pale yellow tint. The children's faces shown at the bottom of the test page look faded, the shades are not vibrant and natural enough.

Open the color rendering settings window on your computer and find the halftone curve. We reduce the yellow color in the settings, increase and adjust the brightness and clarity of the image. We print a second test page with the new settings.

Test page after additional color settings

After adjusting the color rendering, the test page looks more natural: the milky yellow tint has disappeared, the images have become more realistic, clearer, and brighter.

If the color rendering adjustment does not give the expected results, then most likely you are using photo paper that is not suitable for the ink data. In this case, you will not get satisfactory print quality without color distortion even using original inks, not to mention cheaper compatible inks.

In conclusion, it should be noted that the correct selection of ink for inkjet printing is a rather labor-intensive and complex process for the average buyer. Therefore, if you are not confident in your knowledge and abilities in the field of inkjet printing and printer maintenance, it is better to seek advice from professionals.

Before switching to alternative inks or changing ink manufacturers, it is a good idea to conduct a color rendering test to compare print results.

Today I would like to introduce you to a simple test of ink color rendering quality in CMYK mode for 4-color inkjet printers.

This test will allow you to quickly determine the quality of the ink used and, if the result is negative, will allow you to change the ink before performing critical printing work.

I decided to make a small review, since quite often I receive questions about how to independently check the quality of the ink that you plan to refill printer cartridges with. This review will be useful to everyone who is planning to make a choice.

A short theoretical introduction. There are several ways to mix colors CMYK And RGB . The simplest color mixing mode and at the same time the most common is CMYK. Deciphered by the first letters, which determines the colors C yan (blue), M agenta (purple), Y ellow (yellow) and Blac k(black).

This mixing mode has been in use since the advent of printing equipment. Modern printers with 4 cartridges use a group of colors to print images and black to print text. Therefore, it is quite common to find combined colors in one cartridge + a separate cartridge with black ink (most of Canon and HP home printers).

It is the users of these printer models who are quite often interested in the issue of high-quality color rendering; this review will probably be primarily useful for them.

Knowing that images are not printed using a black cartridge, but only color ink, can be used successfully to test the color quality of a particular ink color. What does this mean? Ideally, when sending a black square, which is a graphic file, for printing, the printer determines which colors and in what proportions need to be mixed. More precisely, the graphics program sends this data to the printer buffer. The printer, having received this data, must accurately maintain the mixing proportions and print a perfectly black square.

This is in theory, unfortunately, even with original ink it is not always possible to get a perfectly black print (a headache for photographers who like to print black and white photographs). As a rule, the result is a slightly grayish tint. When using low-quality ink, color loss can occur in any direction. Moreover, not all colors may be to blame, but only one. For example, instead of bright purple, you use carrot, and all other colors (blue and yellow) have perfect color rendition. In this case, your black square will have a burgundy tint.

When testing, you can quickly understand which color is problematic, based on the photo in this review. As you can see from the photo, with the perfect combination of all three colors you should get a perfectly black color. Using this knowledge, you can very quickly find out what quality your ink is and whether it is worth using it in your work.

This must also be taken into account when printing. It’s just that sometimes you hear that pigment ink is used little, even though we print a lot of black and white documents. As it turns out later, documents are printed from a PDF file as images. Therefore, the printer accepts the command to mix color ink. Naturally, the pigment in the black cartridge will not be consumed.

In Canon printers, this test is included as standard in the printer control program. When you print a test sheet, on the left edge, opposite each color, there are black rectangles, which can be used to monitor the quality of color rendering in the manner described above. You will immediately be able to notice if the black rectangle on the test has turned blue or brown. This means something happened to the ink, or one color has run out.

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