Transparent digital negatives
The Easy Digital Negatives program (abbreviated EDN) is intended for printing photographic negatives on transparent foils and other transparent material.
Due to the lack of drivers for printing on transparent materials or significant differences between different photographic techniques, we have to make negative corrections for each old photographic technique. Only with these corrections can we produce optimal negatives or quality photography.
Making a photo without corrections
If we make a photographic negative without corrections (1) or just invert and mirror the photo (2), print and develop it on transparent material, we notice that the final photo is quite different from our original image. A photograph made with the cyanotype technique (3) becomes quite contrasting, and in a photograph made with the salt print technique (4), we lose light tones, and so on.
When we want to find out what happens when using transparent negatives, we can help ourselves with the so-called step wedge file. This file is a photograph in which there is a considerable number of fields with evenly distributed color or grayscale tones. The range of these is most often from entirely black to completely white (5).
After inverting, mirroring (6), and printing the step wedge file, we observe that only about 17 shades on the negative (7) are useful in the cyanotype technique.
When we plot the read color values in the graph, we observe the same values (8). We need to increase this limited range of tones and distribute the colors evenly for a perfect photo.
Making a photo with corrections
In the previous cyanotype printing case, we noticed that only about 17 color shades from our step wedge table are present for making a photographic negative or making a photo in our fictional case (7).
Above and below these tones, all other shades are useless, as they only show completely white or dark tones on a positive image (3).
Our task is to expand these 17 tones (9), we call this to normalize the photo to correct it so that it is “normal” for our eyes.
We have to linearize the color shades or straighten the correction curve with an even distribution of tones according to the table (10).
Now our photo will be displayed correctly. Normalization and linearization can be performed manually, but we will leave this task to the Easy Digital Negatives program. The calculated corrections can be saved in different file types. Most often, values are stored in a curve file, in a gradient map file, or in the latest version of EDN application also in a LUT file.
These so-called Look Up Tables can be standalone or included in ICC profiles.
Once we have made the correction (11), we add it to the photo. These corrections on the negative sometimes change so much that they feel wrong (12). But the final photo will be of much better quality (13) than in printing a negative without correction (3).
Easy Digital Negatives overview
As the name of the Easy Digital Negatives program suggests, using the program is extremely easy, but the program still makes exact corrections for transparent digital negatives. And slightly more demanding users can even change the value of each tone on the negative.
Running the program
The program can be run online or downloaded to a home computer.
Launch the program from the web
If we want to run the program online, we first need to download some files with samples to our home computer.
1. We open a browser and go to www.EasyDigitalNegatives.com.
2. The TestCharts.zip file is located in the Downloads menu. When we unpack the file, we find additional files in it. Important are the files described below, which are intended to create sample tables for use with a scanner or camera.
In case we want to make corrections with the help of spectrometers, we will use the files in the folders i1, Munki, or Argyll.
3. We run the online program via the Run menu and the EDN command.
Starting the program from home computer
If we want to download the program to our home computer, we look for the Downloads menu on the mentioned website.
1. We download the file EDN_Basic2_2.zip.
2. 2. Then we extract to any folder the program file, which also contains the sample table files.
3. 3. To start the program, we double-click the index.html file in the selected folder.
Program window overview
When we run the program, a program window appears in front of us. It consists of three essential areas.
In the first area, (1) we select the type of data we want to use for correction. The second area displays links to files with calculated corrections (2). In the additional area (Show more options), we find the additional types of corrections and some advanced settings (3). The third section shows the correction graph (4).
Before starting the program, we must first select the type of data we want to use to calculate the corrections (5).
We can use scanned or photographed images (Import EDN Images), spectrometer files (Import Spectrometer Files), and for automatic correction of corrections, we need two correction files of type .cube (Combine 1st and 2nd correction).
At the same time, we can open a more significant number of images of samples or other data. It is best to select the desired files from the folder, click on them with the left mouse button, and move these files over the Choose File button (6). When we drop the data to the button, the program automatically calculates the corrections.
Using a more significant number of files is highly recommended, as the calculated correction result will be much more accurate than using a single file with a printed sample.
Images of samples
The image files we want to use can be .jpg, .png, or .gif. You can also open .tiff files with the Safari browser.
Files must have a resolution of 300DPI. The scanned samples made from the EDN_RGB_256 file should be about 1507 px X 1507 px, and the size of the samples made from the EDN_RGB_101 files should be about 1003 x 1087px. The deviation can be +/- 10 px.
Corrections can also be calculated using data obtained using different spectrometers. The program supports various spectrometers, especially i1 and colorMUNKI, and the like.
The program can read data from i1Profiler, and Photo ColorPicker, designed for ColorMunki spectrophotometer, and data from the free Argyll Color Management System can also be used.
Therefore, we can use i1Profiler CGATS CIELab file types (* .txt), X-Rite Color Exchange File (* .cxf) files, and Argyll data with a .ti3 extension. But we will talk more about these below.
Corrections of corrections
Correction of corrections is calculated by opening two .cube files in which the first (7) and the second correction (8) are stored. Immediately after opening the files, the link to the result, and the correction curve’s appearance are displayed (9).
Download file type
Links to corrections files (10) are located in the middle of the EDN dialog box. The links become active as soon as we open the corrections files. The program calculates the correction in a few milliseconds. The basic types of patch files that we see in this window are as follows:
• LUT 1D is an increasingly popular data type. The data in this file is written in a relatively simple way, but the correction stored in this file is of exceptional quality. These files can be used in almost all photo editing programs. It can be used in Adobe Photoshop, with the help of plug-in in the GIMP, and is also quite popular in Affinity Photo and other similar digital photo or video processing programs.
• Adobe gradient map is a kind of interactive LUT file that can only be used in Adobe Photoshop. As mentioned, the corrections stored in this file are of exceptional quality.
• Adobe Photoshop Curve is a curve that we used at the beginning of the development of digital negatives technology to make corrections. As mentioned, the quality of these fixes is quite poor. But because it is still used by a considerable number of less demanding photographers today, I kept it in this version of the EDN program.
• The Screen Proof LUT 3D file is a high-quality file of 3-dimensionally presented LUT data. This file does not contain a correction, but a color scheme, which shows the final appearance of the positive image during the photo manipulation. But more on that below.
Additional correction files
We can find the remaining correction files in the area that appears by clicking the Show more (less) options button (11).
The first and second links of this section are corrections that can be used in the free GIMP program (12). A GIMP curve is a file in which the results are displayed in the form of a curve. Of course, better is the GIMP gradient map, which is intended for slightly more demanding users.
By clicking on the following link, we can download the LUT files again. This time, the data is stored with 52nd and 256th control points. These files can be used to change the desired control points manually. Of course, these two files are intended for very demanding users who want to control every color on the negative.
The Scanned normalized data file stores normalized scanned data. This file is intended for users who want to correct it manually. The data is saved in the standard CSV format (13). We can open this file in Microsoft Excel or Mac Numbers, or any spreadsheet or text program.
We save the corrections by right-clicking on the desired link and selecting the command Save link as .., or Download Linked File As and the like.
In the event of higher computer protection, a warning appears, asking if we want to download the file (14). If we want to transfer data, we must allow the transfer.
Coating check file
If we open a positive image (14) of the sample file EDN_COATING.tif (15) in the EDN program, the correction files’ links remain inactive.
In this case, the program displays only the coating quality (16) in the graph window. But we will also talk more about this below.
Graphical display of results
In the lower area of the program window is an area for the graphical display of results. If we open images or spectrophotometer data with the program, the so-called linearized correction curve (17) is plotted.
In the lower right corner of the graph, the program displays the approximate value of D-max, the maximum print density on our sample. This approximate D-max calculates the program from the so-called Lab value. In case we open a large number of files, the message multi is written instead of the value D-max.
If we click on the surface of the graph, the second curve is displayed instead of the first, linearized one. This curve shows the scanned colors’ values, i.e., the color values before corrections (18).
To a certain extent, we can also check the quality of the coating on the paper in this window. This data is the same as the data in the Scanned normalized data (.csv) file.
As already mentioned, if we insert an image of the EDN_COATING.tif file into the program, in the graphic area, the paper coating quality (19) is displayed. Since no corrections are calculated, the Download file type (10) area is not activated.
This coating quality data function is only intended to check our coating technique’s quality visually.
Additional program settings
By clicking on the Show more options button, we can display two additional settings for working with Easy Digital Negatives (20).
Simulate Paper Color
The Simulate Paper Color command (21) works in conjunction with the Screen Proof LUT 3D file.
If we check the selection, the print preview values for simulating the printed colors become slightly darker. Instead of automatically calculating white-balance, the program adds to the print preview file the color of the paper.
Use the Gamma Line
The Use the Gamma Line command (22) allows us to make a theoretically perfect correction of color values. The theoretically correct correction curve should be as close as possible to a straight line.
But in practice, if we calculate each control point correctly, we will notice a jump in values in the area of light and dark tones (23).
And if we want to avoid this apparent leap of tones, we have to flatten the curve a bit (24).
Unfortunately, we lose some light and dark tones with this operation, but some users prefer gentle transitions rather than perfect shades.
Instructions for using the EDN program
Corrections of transparent digital negatives are performed in a few steps. Here we present only a brief overview of the process. A detailed description follows below.
First, we download the Step Wedge files needed to measure the patches from the Internet.
The step wedge file is mirrored, inverted, and printed on transparent film.
To make a sample, we need to know the standard exposure time, but we can also use the approximate time.
We then create a positive image of the step wedge file.
The sample is digitized or scanned, photographed, or measured with a spectrometer.
If we photographed the sample, we need to change the size and resolution of the image.
We create a correction file and a file to preview the printed image. We save the file with corrections in the appropriate folder.
We open the image to which we want to assign corrections.
We edit the image as desired, add a correction file, we mirror and invert the image. The corrected image is then printed.
Step by step to the negative
Although it is not in my nature to start describing the work process before introducing the reader to the basic concepts, I opted for just such an approach in the case of this handbook.
Many users have mentioned to me that they prefer instructions, which lead to a quick result, step by step at the very beginning, without any theory. So let it be so.
But I did not omit the theoretical explanation. I added it to the second half of the book.
In the first example, we will create a transparent negative with Easy Digital Negatives 2.2, without using ColorBlocker. The use of EDN ColorBlocker will be described in a separate section.
What do we need?
To make transparent films with Easy Digital negatives, we need almost nothing that the average user would not already have at home. In addition to being extremely easy to use, the EDN program also works in practically all computer environments, on all printers, …
• So we need a computer (desktop, laptop, PC or MAC, tablet, etc.) with any operating system, on whose web browser is installed.
• We need a device for printing negatives, i.e., any printer of any type and brand.
• Samples for calculating corrections of transparent digital negatives can be read with a camera, scanner, or spectrometer. In this example, we will use a scanner.
• For photo processing, we can use any slightly better digital photo processing program. We can use GIMP, Adobe Photoshop, Affinity Photo, Adobe LightRoom, etc. Since most users use Photoshop, we will also use this program to show examples.
• Then we need transparent films, chemicals and maybe something else.
When making transparent digital negatives, we must adhere to some basic requirements that enable the production of quality and consistent results.
When we choose the selected photographic technique, we must always use the same formula to produce a sensitizer; use the same paper or other carriers of a photo; always choose the same exposure time; the same source of light; apply the sensitizer in the same manner; develop and wash the photo with the same additives and in the same way, with equal time, chemicals, etc.
In short, the work must always be carried out under the same conditions!
Making corrections with EDN
As mentioned in the introduction, we will use the Easy Digital Negatives 2.2 online program to calculate corrections. We chose Adobe Photoshop as the basic program. But because the commands used to make fixes are almost standard, the user will easily find them in other applications.
1. Downloading a sample step wedge file
When I was determining the optimal number of colors to look for negative corrections years ago, I discovered that it is better to use tables with 256 colors instead of the previous 100 colors. The corrections are much more accurate. For our example, we will need a file named EDN_RGB_256.tif.
1. Open any web browser and go to the www.EasyDigitalNegatives.com.
2. In the Downloads menu, find the file TestCharts.zip (1).
3. Right-click on the file name and download the file to your home computer.
4. Unpack the file.
5. In the TestCharts folder, find the file EDN_RGB_256.tif.
2. Printing a sample file
1. The printing process is quite simple. The EDN_RGB_256.tif file is opened in the photo editing program (2).
2. Invert the file; this is, change it to a negative image.
3. In the next step, mirror the image (Flip Horizontal) (3).
4. Load the transparent film into the printer and select file> Print.
5. If you have the option, select the “Printer Manages Colors” option (4).
6. In the advanced printer settings, choose the best print quality (5) and turn off all automatic print modes, or select manual print settings (6).
7. The photo of the sample should not be printed in grayscale but in color mode.
8. Print the final photo and wait for about an hour for the ink on the transparent film to dry completely.
9. If possible, save the printer settings, as they will now also be used for printing samples.
3. Exposure time
The first practical step in making digital negatives is always to find the optimal exposure time. But because these instructions aim to introduce the average user to the world of digital negatives as quickly as possible, we will omit a description of this process. We will talk about a simple correction of this time below.
4. Creating a positive image
The production of a positive image depends on the photographic technique we use. However, the transparent negative with the printed side is often turned towards the paper surface (7). The paper and negative are then squeezed together and exposed with the selected exposure time (8).
Correction of exposure time
When the image is developed, we can get an accurately exposed sample. In this case, light tones will be slightly visible on the bottom of the sample (9).
If we overexpose the sample, we will not notice any white tones in the lower part of the step wedge table (10). In this case, we shorten the exposure time by half. So we place the negative again on the prepared paper and expose the image for half less time. Then we repeat this process until we notice white tones at the bottom of the sample (9).
If we exposed the sample with too short exposure time, we would notice a white, unprinted area (11) in the sample’s lower part. In this case, the exposure time must be extended by 2x. We repeat the process until we obtain the optimal exposure of the sample (9).
5. Scanning the samples
Once the correctly exposed sample (9) has been produced, the sample must be digitized. As mentioned, we will use a scanner in our case.
Since scanners’ settings are entirely dependent on the manufacturer and even on individual models, it is impossible to describe the settings for each scanner accurately. We will, therefore, present only scanning using Mac’s Image Capture program, although the settings will be similar to other scanning programs. Thus, the scanning technique described below is generically useful for most scanners and adapted to the rapid achievement of results on all kinds of scanners.
1. We place the sample in the scanner (12), but before scanning, we adjust some settings.
2. First, we select color scanning with 24-bit depth or Millions of colors (13).
3. If there is an option, we choose the best scanning quality.
4. The scanning resolution of our samples is 300 dpi (14).
5. Then we select the Color scanning (15) or sRGB color space.
6. We click on the Overview or Preview button and select the scan area in the photo. This area is limited only to our sample. If we have the option, we can enter the exact value (1507 x 1507 px). We position the scanning surface as precisely as possible in the corners of our sample (16).
7. We scan the sample by clicking on the Scan button.
NOTE If you are reading spectrometer data via ARGYLL, you must use the “-n -l” switches, for example “
chartread -n -l EDN_ARGYLL_i1_RGB_101“.
6. Preparing the sample for reading
If the sample has not been previously adapted to work with the EDN program, it must be resized to the appropriate size. Then we change the resolution of the sample to a resolution of 300DPI. There are many programs for digital photo processing, but there are even more commands that can be used to change the properties of photography.
If we followed the instructions and scanned the image with 300 dpi resolution, we do not need to change the image resolution. However, in the case of capturing a sample with a camera, changing the resolution is necessary. We have to use the Resample image command.
The links below lead to quite a few procedures we can use to resize an image. The videos show how to work with a ColorBlocker file, but all steps are the same for working with EDN files.
7. Making negative corrections
Making corrections in Easy Digital Negatives 2.2 is extremely easy.
1. If you are using the EDN web program, open any web browser and go to the www.EasyDigitalNegatives.com.
2. In the Run menu, click the EDN 2.2 command.
3. Files of scanned samples can be opened in the program by clicking on the Choose Files button. But it is even simpler to select several files with the mouse and drag them to the Choose File button (17).
Whenever possible, we open multiple sample files simultaneously, as the program calculates much more accurate corrections by calculating the average value of the data. The more samples we insert into the program, the more precise the correction results will be.
8. How to save corrections
The moment we open or drag and drop the sample files into the Choose File button, the EDN program calculates the corrections. Corrections are shown in the Download File Type area.
The program saves the correction in different file types to be used in as many various applications as possible (18).
The first two files are for Adobe Photoshop users. The Adobe Photoshop Curve file stores corrections in a curve. The correction stored in the Adobe Gradient Map file provides a much better correction. Slightly more demanding users use this type of data.
By clicking on the LUT 1D link, we can download the so-called LUT file. The data in it is written in a straightforward format, but the correction stored in this file is very accurate. These files can be used in almost all photo editing programs. It can be used in Adobe Photoshop, in the GIMP (with an add-on installed), in Affinity Photo and other similar applications.
By clicking on the Show More Options button (19), we can display additional types of files with negative corrections.
Here we first find a GIMP curve file. The GIMP gradient map is again intended for slightly more demanding users who want to use better quality corrections.
1. We save corrections by right-clicking on the desired correction link and selecting the Save link as… command, or Download Linked File As and the like.
2. We will save a curve file for Adobe Photoshop (Adobe Photoshop Curve) and a Screen Proof LUT 3D file, which we will use to preview the printed photo.
In the case of higher computer protection, we will notice a warning that will ask us if we want to download the file. If we’re going to transfer the data, we need to confirm the transfer.
NOTE When we open the files in the EDN program, the program calculates the corrections in 1/1000 second. Changing additional settings no longer has any effect on the value of the calculated correction. If we want to change the settings, we need to refresh the program’s webpage, then change the settings and reopen the files.
9. Adding corrections to the photo
Because there are a significant number of digital image processing programs on the market, and because the EDN program can save corrections to a large number of different file types, we cannot describe all the procedures for applying corrections to the image.
For ease of understanding, we’ve described the use of the most popular correction, the Adobe Photoshop curve. And let me remind you again, the correction stored in the curves is of the lowest quality.
I’ve also made quite a few videos that show how to add corrections to various programs. The videos are intended for inserting increasingly popular LUT and Gradient map corrections, which we created with the EDN ColorBlocker program. But the process of adding these corrections is the same as adding the corrections we made with Easy Digital Negatives.
Adding a print preview file
Using a file that colors the photo with the colors we will see printed on the positive image is not mandatory, but recommended.
1. We open the photo we want to print in the photo editing program.
2. If the image is in color, we first change it to a black and white image (Image> Mode> Grayscale), and then back to RGB mode (Image> Mode> RGB Color). We can also change it by reducing its saturation.
3. To save the print preview file, we click the Screen Proof LUT 3D link.
4. We insert the preview file into Photoshop as follows.
5. We click the Adjustments tab (20).
6. Then we click on the Create New Color Lookup button (21).
7. The Properties tab (22) opens, in which we click on the Load 3D LUT option (23).
8. We can now find our preview data file (LUT3Dscreen.cube) and load it to the program. The image will colorize the image with a color of the cyanotype (24).
9. We will immediately notice that the photo is a bit too contrasting, too soft, etc.
10. We Click on the bottom layer of the photo to edit the photo (25).
11. When our editing is done, we delete the preview layer with the LUT3Dscreen.cube file.
12. We now add a negative correction to the image and print it.
Adding correction to the image
We will fix the negative with the corrections stored in the Adobe Photoshop curve file.
1. At first, we run the image> Adjustment > Curves command.
2. We load the curve by clicking on the Preset options button, choosing the Load preset command (26).
3. In the dialog box, we search for our file with the custom curve. Then we select it and click the Load Preset button.
4. When we close the dialog, our photos change (27). A change in the photo’s look should not bother us, as this is the correct appearance of a corrected image.
5. We change the image to negative (28) by inverting and mirroring it (Flip Canvas Horizontal).
6. When the image is converted to a negative, we print it with the same settings as we used to print the first sample table.
7. When the negative dries, we make a photograph with a correction, which is much better (29) than a picture made without a correction.