The Ins . . . Move Your Workflow Forward with Large-Format Scanners (Cadalyst Labs Review)1 Apr, 2007 By: Henrik Vestermark
Cadalyst Labs examines the latest large-format scanners from Colortrac, Contex, Graphtec, GTCO CalComp, Oce and Paradigm Imaging.
It's been one year since Cadalyst last looked at large-format scanners and more than two years since it published a large-scale comparative review. New scanners have arrived on the market, and it's about time we review these latest products with regard to CAD users' needs. But what are those needs?
Most large-format scanners are color scanners, yet less than 10% of CAD users have a well-defined need for color scanning. If anything, most buyers are looking at color scanning only to hedge against future needs, but they're not willing to pay a premium price for features that they might need some day. And even though today's CAD scanning typically requires a 200–400dpi range, most scanner manufacturers deliver units that offer resolution as high as 4,800–9,600dpi. Most CAD customers also need only 500–2,000 scans per year, something that can be done easily with less elaborate products. And when I scan an E-size drawing, does it really matter that it completes in 6 seconds as opposed to 18?
Scanning speed may not be an issue, but total cost of ownership is. On average, a new scanner should last five years (which also is the depreciation period for most companies), so it becomes important to figure out the actual purchase price plus the total cost of operation during those five years. Most CAD buyers are looking for a scanner purchase that maximizes value.
Cadalyst invited the traditional scanner manufacturers to participate in this review. Colortrac, Contex, Graphtec, GTCO CalComp, Océ and Paradigm sent scanner models suitable for the CAD market. All offer warranty options for five-year periods. All of Contex's on-site warranty options are handled by local distributors or dealers.
In general, the state of the scanner market is good for today's CAD community. All of the tested scanners passed the minimum requirements for the CAD industry—but I found no slam-dunk winner. All scanners have advantages and disadvantages, and individual users must evaluate each based on their personal preferences.
First of all, abandon the myth that optical resolution is equal to scanning quality. Optical resolutions are indicators of scan quality, not measures of it. To measure the quality, you must also consider a scanner's optical system, mirrors, CCDs (charge-coupled devices), glass plate and the illumination systems. For this review, I measured scanning quality by seeing how many line pairs per milli-meter each scanner could resolve in scanning resolutions between 200 and 400dpi. This value gives a better idea about a scanner's performance potential, rather than just relying on the optical resolution.
Next, I looked at each scanner's vertical and horizontal accuracy. I didn't measure a full 36"—rather, I measured a randomly selected 6" distance within the scan area. Most scanner vendors electronically adjust the 36" distance to match within ±0.1%, but only one of the vendors tried to calibrate each individual pixel. As expected, I obtained below-scanner specification accuracy, but I found it to be a much more realistic value for a scanner working in a CAD environment.
Finally, I looked at scanner performance and measured scanning speed. To do this, I started the clock each time I pressed the scan button and stopped it when each image had been scanned, converted to the destination file format and saved to disk. I saved black-and-white scans as the industry standard TIFF Group 4 file format and grayscale images as TIFF uncompressed. I then measured scan speed for scanning resolutions of 100, 200, 300, 400, 500 and 600dpi and took the combined average scan time for the 200-, 300- and 400dpi speeds because these resolutions are the most commonly used in the CAD industry. The measured scan speed is far from the scanner manufacturers' specification because I measured real-world times that take into consideration the USB scanner interface, PC compression, saving of the file format and the notorious lag time that exists between pressing the scan button and having the scanner actually scan the first line of data. This pause is typically 2 to 3 seconds. All scanners seem to have this lag time.
After testing scanner quality and performance, I evaluated the scanners in commercial terms. I aligned all of the scanner prices in this review so they contained the same configuration of a scanner, scanner stand, scanner software and an on-site service warranty, although some vendors sell stand, software and service separately. On-site service varies from none to as much as three years of service. Users can buy additional on-site warranties for as much as five years of service. Unfortunately, Contex declined to specify the price for on-site warranty, which made it impossible to fairly compare total cost of ownership. Readers will need to call their preferred sellers for actual pricing.
To muddy the waters even further, some scanners are monochrome-only, while others are or can be upgraded to 8- or 24-bit color. The best way to decide if you should buy a color scanner is to determine whether you'll need color capabilities within the next five years. If not, look for a monochrome-only scanner (or the least expensive color scanner available to you). If you expect that you'll need color scanning within the next five years (the lifetime of your scanner purchase), buy either a color scanner or a scanner that can be upgraded to color.
An accompanying online feature table (www.cadalyst.com/0407scanner-table) will give you some idea of the covered devices' capabilities. You can find more information and test results at www.theothersolutions.com/cadalyst/review2007/scanners.htm.
Colortrac Cx40 and Gx42
Colortrac submitted two scanners for this review: the Cx40 and the Gx42. Colortrac's Cx40e yielded a second-best line pairs per millimeter result of 4.4 but was behind other scanners in speed and horizontal accuracy (0.75% is high and on the borderline of what is acceptable). The more expensive Colortrac GX42e scanner has a surprisingly lower line pairs per millimeter result of 3.9 when compared with the Cx40e.
Colortrac Cx40. The Cx40 Series comes in three different flavors, starting with the entry model Cx40m, a monochrome scanner that is priced at $10,889. The CX40c adds color for $11,989. The top-of-the-line version, the CX40e, costs $13,089 and further increases color-scan speed. The upgrade procedure is simple. You simply run a program that updates the scanner to the next version.
Colortrac's Cx40 scanner provides good-quality scans and adaptive thresholding cleanup tools.
The Cx40 weighs in at 60lbs and can easily fit on an office table, but most customers buy the optional stand so it's easier to move around (particularly if they share the scanner). The installation manual is excellent and installation is easy, so there's no need to pay for outside installation.
Colortrac's SmartLF software is included with the scanner and provides very basic scan-to-file and scan-to-print features. I recommend that users buy the ScanWorks scanner application for an additional $574. It provides complete control of the scanning process so users can tweak every needed parameter for optimal scanning results. The Cx40 supports the USB2 interface and, like most other scanners, can auto-detect the image size. Batch scanning works uninterrupted and continues in this mode until an operator cancels batch mode.
The ScanWorks interface is among the best of the tested scanners. It isn't cluttered, and the controls are organized in logical groupings to ease the learning curve. Another area in which ScanWorks excels is the adaptive threshold tool, which helps turn bad or deteriorated blueprints or sepia drawings into useful images. ScanWorks is the only software that allows users to tune the adaptive threshold settings after the scan (other scanners require a rescan after changing the settings). This feature makes it a joy to improve the images —and it also provides the best results. I recommend purchasing the ScanWorks software to drive Colortrac scanners. ScanWorks can be used as an image viewer, in which you apply the same control you as do with scanning. The viewer also supports multiple windows so you can compare images.
The Cx40 scanner's vertical and horizontal accuracy were 0.22% and 0.75%, respectively. The horizontal result was the least accurate of the tested scanners. However, the Cx40 came in at 4.4 on the line pairs per millimeter test, the second best of all the scanners in this article. The average scan time for 200-, 300- and 400dpi black-and-white E-size (36" x 48") drawings was 24 seconds per scan, which is slower than most of the other tested scanners.
Colortrac Gx42. The Colortrac Gx42 is a 42" color scanner that comes in three different options—the entry model Gx42m ($12,589) monochrome version; the Gx42c ($13,689), which adds color; and the top-of-the-line Gx42e ($14,789), which increases the color speed. As with the Cx40 models, future upgrades can be managed by a computer program.
The Gx42 scanner weighs 113lbs and supports the USB2 interface. Like most scanners, it can autodetect an image's size. The installation manual is excellent, making it easy for users to install the scanner themselves. As with the Cx40 models, users begin by installing the low-level scanner drivers and then the free scanning software SmartLF. The SmartLF software provides very basic scan-to-file and scan-to-print features. It's a good product for novice scanner operators or for environments where simplicity is needed. However, I recommend the company's optional ScanWorks scanner application. ScanWorks has some nice features that can help users integrate their scanner application into other programs, such as indexing software and Adobe Photoshop. Users can set ScanWorks to automatically launch a third-party program after each scan, and the image is transferred to the new application using a DDE/OLE interface.
I measured the vertical and horizontal accuracy as 0.20% and 0.11%, respectively, and these results were among the best of the reviewed scanners. The line pairs per millimeter test yielded a 4.7 value, right at the top. The average scan time for 200-, 300- and 400dpi black-and-white, E-size drawings was 33 seconds per scan—the slowest in this roundup. However, by the time you read this, Colortrac should have released a firmware update that can double the black-and-white performance.
HAWK-EYE G36 and CHAMELEON G600
Contex requested that Cadalyst review four of its scanners. Because of the similarity between the machines, I reviewed only two: the HAWK-EYE G36 and the CHAMELEON G600 scanner, both of which are 36" scanners. The Plus versions of these scanners provide marginally better color performance. I didn't test the CRYSTAL G600, which is identical to the CHAMELEON except that it scans 42"-wide documents. I didn't test the PREMIER G600 either, which is similar to the CRYSTAL G600 except that it only performs monochrome scanning and has no upgrade path to color. Buyers should check the prices for optional two-year onsite service packages for all Contex models, because they could alter the price value of these scanners.
HAWK-EYE G36. The HAWK-EYE G36 is a fast monochrome and color scanner with a very attractive starting price of $10,890 (including the optional WIDEimageNET software, which is valued at $990). This scanner is a good choice for users who need color capabilities or who want to protect their future investment. The scanner's only weakness is its 200dpi optical resolution, which is lower than the other scanners reviewed. The HAWK-EYE is a single-camera system, which eliminates potential stitching problems sometimes found on multiple-camera systems. Contex has done a great job in improving the image by using quality lenses and image processing to boost performance for this single-camera scanner.
The Contex HAWK-EYE G36 comes with WIDEimageNET software, which is robust and feature-rich.
The HAWK-EYE G36 can easily fit on an office table, but most customers buy the optional $890 stand to make it easier to move the scanner (particularly if it's a shared unit). Installation is easy; I recommend that users or IT departments handle it. A setup guide with pictures and easy-to-follow descriptions show users how to set up the scanner properly and perform basic calibration. The HAWK-EYE G36 supports both USB2 and the FireWire interfaces.
Contex WIDEimageNET software has been around since 1998 and is considered one of the most stable scanner programs available. It's a feature-rich program that addresses CAD needs and more. When scanning difficult CAD drawings, users can quickly and easily view a preview and fine-tune the scanner parameters for a better scan. A nice feature in Preview allows users to click on any point in the over-view window and have the scanner automatically reposition the drawings and scan that area.
Contex scanners support 37 black-and-white, grayscale and color formats, including JPEG, PDF, TIFF and Cals Group 4. Only one thing is lacking: the ability to view more than one file at a time. This is something that other scanners support.
Accuracy for the HAWK-EYE G36 was measured as 0.11% in the vertical direction and 0.25% in the horizontal direction. The line pairs per millimeter was 3.3, which is better than expected and in-line with most CAD requirements. The average scan time for 200-, 300- and 400dpi scanning was 16 seconds, making this a very fast scanner.
CHAMELEON G600. The Contex CHAMELEON G600 is a 36" monochrome and color scanner base priced at $11,900, The product comes with a stand and WIDEimageNET scanner software. The CHAMELEON G600 is offered in two forms: the base model and the plus model, which costs $2,000 more. The Plus upgrade requires a credit-card–sized card a user slides into the scanner to improve color performance from 0.6ips to 1ips and maximum resolution from 1,200dpi to 9,600dpi. From a CAD-only perspective, it's probably not worth spending $2,000 for this upgrade, unless you do a lot of color scanning.
Installing the CHAMELEON G600 was just as easy as the HAWK-EYE scanner. The scanner weighs approximately 126lbs, so it takes two people to lift it out of the box. The CHAME-LEON and HAWK-EYE use the same calibration software and calibration target. The CHAMELEON has three cameras, so the calibration software ensures correct stitching of the camera boundaries. The CHAMELEON has motorized cameras, and the calibration software automatically tilts each camera until it achieves correct vertical height.
The WIDEimageNET software is stable, mature and fast. Most other programs lag behind in the scanning process, but WIDEimageNET follows the scanner in real time and completes at the same time the scanning is done. The software interface adapts to whatever scanner is used; for example, if the scanner doesn't scan in color, that option is unavailable. This results in a clean interface with less clutter than that of other scanning software.
The CHAMELEON G600 supports 37 black-and-white, grayscale and color formats, including JPEG, PDF, TIFF and Cals Group 4. WIDEimageNET also supports the newer JPEG2000 standard for color and grayscale images.
The line pairs per millimeter result was measured at an impressive 4.7, the highest, for this 508dpi optical-resolution scanner. This result is the best that I have measured in the scanner industry and exceeds CAD requirements. I measured the horizontal and vertical accuracy at 0.26% and 0.3%, respectively. Later on, I performed a vertical-accuracy adjustment that improved the vertical precision to 0.03%. The 0.26% horizontal accuracy is above the company's stated specification but is acceptable for the CAD industry. The average time for 200-, 300- and 400dpi scanning was 10 seconds per E-size black-and-white scan—a very fast scanner.
Graphtec IS200 Series and CS500
Graphtec focuses on its 42" wide scanners. At the bottom of the price range is the IS200 Base monochrome scanner ($9,995). You can upgrade the Base model to a Pro ($11,995) for faster monochromatic scanning speed. If you need color, you can further upgrade to a ProLC ($13,995), which gives you 8-bit color, then to a 24-bit color scanner, the CS500 model ($17,995). This tiered upgrade path makes the Graphtec IS200 an inter-esting option. The upgrade price is the difference between the list prices.
The company's installation manual is concise and makes it easy to assemble the support stand and install the low-level drivers, ScanMaster 21+ scanner software and cali-bration tools. Users can connect the scanners via USB2 or Ethernet. The Ethernet installation requires more setup steps on the PC. I used the USB2 interface for my testing, and basic calibration took less than 10 minutes using the included calibration sheet.
It may take awhile to get used to the ScanMaster21+ software interface. The main screen has a quick-scan setting for destination file folder, filename and drawing type. Users only need to press the Scan button, and the scanner scans and displays the image. Users who want more control can select Scan/Scan to get into the Scanning dialog box, where they can set all the other scanner parameters. ScanMaster 21+ supports multiple-file viewing.
Graphtec supports only eight black-and-white and color file formats. It has all the different variations of TIFF such as uncompressed, Packbits, Group 3 and Group 4, as well as JPEG for color only.
The scanning quality settings—fast speed, normal and high quality—are helpful. Depending on individual scanning needs, users can set a scanner to perform at an appropriate speed for the quality needed. For a normal drawing, the fast speed and normal modes would be appropriate, whereas more difficult drawings with tighter lines might require the high-quality setting that detects closer lines. I measured the line pairs per millimeter as 4.4 in scanning resolution between 200–400dpi in high-quality scan mode, which provided 50% better quality than when scanning in normal or high-speed mode. Although it's a 600dpi optical scanner, the normal mode sacrifices some of the quality that a 600dpi optical scanner should be able to deliver. The horizontal and vertical accuracy were measured as 0.167% and 0.14%, respectively.
Users can set up the Graphtec IS200 ProLC scanner with its quick-scan setting, which manages destination file folder, filename and drawing type.
Unless scanning quality is not an issue, I wouldn't recommend the fast-speed mode or the normal mode. The normal mode doesn't produce significant higher line pairs per milli-meter than a competitor's 200dpi optical scanner.
The average scan time for a 200-, 300- and 400dpi black-and-white E-size drawing was 20 seconds per scan using the high-quality mode. The scanning speed is in the middle of the tested scanners.
ScanPlus 6 LF436 and ScanPlus 6 LF542
GTCO CalComp submitted two scanners for this review: the ScanPlus 6 LF436 and the ScanPlus 6 LF542. The ScanPlus 6 LF436 stands out by offering color scanning from the base price of $10,900, including two years of on-site service. The ScanPlus 6 LF542 is a monochrome-only scanner, so buyers should be sure they don't need to scan color drawings before purchasing that product.
ScanPlus 6 LF436. I'll start with the ScanPlus 6 LF436, a single-camera scanner that avoids the stitching problems of multiple-camera systems (making it particularly suitable for the CAD environment). The LF436 is only a 200dpi optical scanner, which at first glance could put it into the low-quality area of the scanner spectrum. The resolution probably doesn't provide high enough geometrical accuracy for GIS operations, but it's good for CAD. However, the design is good, and the company has been working diligently to increase the quality with improved lenses and image processing. The result is a remarkably solid, high-quality scanner that fits the needs of the CAD environment.
The monochrome ScanPlus 6 LF542 scanner uses a three-camera system with an optical resolution of 508dpi to provide scan quality of 4.7 line pairs per millimeter—the highest result of all reviewed scanners.
The ScanPlus 6 LF436 provides 10ips black-and-white scans with a maximum resolution of 1,200dpi and fast 1.5ips color scans. If this performance isn't enough, users can upgrade to the plus version by sliding a credit-card-sized card into the scanner. The plus version increases the maximum resolution to 9,600dpi and the color scanning speed to 3ips. The Plus version exceeds normal CAD needs, so I would recommend buying the base version and saving roughly $2,000.
As with the other tested scanners, the installation was smooth and shouldn't present any problem for the average CAD user. The ScanPlus 6 LF436 can fit easily on an office table; however, most users will want to buy the optional $890 stand that makes it easier to move and share. Installation is easy; users can do it themselves or let their IT departments handle it. The scanner comes with an illustrated setup guide that has easy-to-follow descriptions for setting up the scanner and performing basic calibration. The ScanPlus 6 LF436 supports both the USB2 and the FireWire interfaces.
The included WIDEimageNET software is the same software that Contex provides. WIDEimageNET supports 27 black-and-white file formats and 10 different grayscale formats, including JPEG, PDF, TIFF and Cals Group 4.
The ScanPlus LF436 generated 3.3 line pairs per milli-meter scanning quality, an excellent result for a 200dpi optical scanner. I measured the vertical and horizontal accuracy as 0.11% and 0.25%, respectively. Again, these are great results from a single-camera system in which you'd expect the inherent spherical errors in the camera-and-lens configuration to dominate. As a matter of fact, the ScanPlus LF436 supports accuracy lens enhancement, which ensures that each pixel is digitally positioned to minimize inaccuracies. I measured the horizontal accuracy as 0.5% without accuracy lens enhancement. The average scan time for the 200-, 300- and 400dpi scanning of an E-size, black-and-white document was 16 seconds per scan, placing it in the middle of scanner performance for this roundup review.
ScanPlus 6 LF542. The ScanPlus 6 LF542 42" monochrome scanner is designed for the CAD market. It's a three-camera system with an optical resolution of 508dpi —more than adequate for CAD users. The product comes in two formats—a base version ($10,900) with a scanning speed of 6ips and a plus version ($12,900) with a 12ips scanning speed. The ScanPlus 6 LF542 is good for digital archiving projects that include scanning all of your black-and-white and/or grayscale drawings into a digital archiving system. Be sure that your future needs don't include color scanning, however, because this scanner can't be upgraded to color.
The installation and calibration process was easy. The calibration process ensures correct stitching between the camera's boundaries. The whole calibration process took less than 10 minutes to complete. The ScanPlus 6 LF436 supports both the USB2 and the FireWire interfaces. The included WIDEimageNET software is the same as that used in the ScanPlus LF436 and Contex scanners.
As with all GTCO CalComp scanners, the ScanPlus LF436 supports autosize detection, which is handy if you need to scan many drawings of different sizes. This function lets users avoid the tedious job of measuring each drawing before scanning.
If monochrome-only fits your needs, the ScanPlus LF542 is a high-quality scanner for the money. The 4.7 line pairs per millimeter scan quality was the highest result in this roundup. Horizontal and vertical accuracies were measured as 0.26% and 0.3%, respectively. I also performed a vertical accuracy adjustment that improved the vertical precision to 0.03%. The 0.26% result is above the company's stated specification but fully acceptable for the CAD industry. The average scan time for a combination of 200-, 300- and 400dpi E-size, black-and-white drawings was 10 seconds per scan—a very fast scanner. The scanning performance was at the top of this review roundup, with average accuracy.
The Océ CS4136S is a high-quality scanner with hardly any downsides, except for its entry price of $16,100. Its 4.7 line pairs per millimeter score combined with scanner performance and accuracy to make it the best in this roundup review. The Océ CS4136S comes standard with a stand and Océ Scan software. The scanner includes one year of on-site service, but buyers can purchase additional service for $1,550 a year. The Océ scanner is a fast monochrome and color scanner at the upper end of the price range of the reviewed scanners. If you need faster color speed than the 1200dpi at 1.5ips with the CS4136S, you can upgrade to the CS4136QS model, which offers 9,600dpi at 3ips color for an additional $2,000. Most CAD users don't need this much scanning power.
Installation of the CS4136 went smoothly. Océ recommends hiring the company to install the scanner at your site for an additional $670. The scanner weighs 126lbs and requires two people to physically set it up, but I found that the electronic installation manual is easy to follow. I installed the scanner, the Océ Scan software and the low-level drivers without incident. In my opinion, most customers would be able to install these items successfully.
The Océ CS4136S provides exceptional quality—its 4.7 line pairs per millimeter score, combined with scanner performance and accuracy, is the best in this roundup review..
The Océ Scan software is easy to learn. All buttons and menus are logical and the learning curve is fast. The Océ Scan software does, however, support a lot of features that aren't typically needed in the CAD community. To scan, users must set up three basic scan parameters: scan mode, resolution and document size. Based on these basic parameters, users can fine-tune a specific scan setting for chosen scan modes. Unlike some of the other scanner manufacturers, Océ adjusts its dialog box based on your settings to eliminate clutter.
For fine drawings, scanning is smooth and parameters rarely require tweaking. For poor-quality blueprint or sepia drawings, users will need adaptive threshold scanning to clean the images up. Océ's scan software allows you to adjust the adaptive level in 10 steps (from –3 to +6). The user-friendly levels usually are enough to obtain acceptable scans out of these drawings.
Océ scanners support 27 black-and-white file formats and ten grayscale formats, including JPEG, PDF, TIFF and Cals Group 4. Only one thing is lacking—the capability to view more than one file at a time, something that both Colortrac and Graphtec scanners support.
The line pairs per millimeter was an impressive 4.7 for this 508dpi optical-resolution scanner. This result was the best that I've measured in the scanner industry. The horizontal and vertical accuracy were initially measured as 0.26% and 0.3%, respectively. I then performed vertical accuracy adjustments that improved the vertical precision to 0.03%. The 0.26% is above the company's stated specification and acceptable for the CAD industry. The average time for 200-, 300- and 400dpi scanning was 10 seconds per E-size black-and-white scan, making it a very fast scanner.
Paradigm ImagePRO Gx42
The Paradigm ImagePRO Gx42 scanners from Paradigm Imaging are its first own color scanners. The ImagePRO Gx42 series comes in three different styles: the entry model Gx42m (monochrome, $11,995); Gx42c (adds color, $15,995); and Gx42e (even more color speed, $17,995). The upgrade procedure is simple—users just run a program to update the scanner to the next version.
The ImagePRO Gx42 includes ImageFLOW software, Paradigm's new all-in-one package that allows you to scan, preview, print and copy images. This software is included with all ImagePRO scanners at no additional charge. ImageFLOW software truly enhances operator experience. All buttons are logically placed with a left-hand side view, a preview and right-hand side controls. The three main functions for scanning, printing and copying are in the lower right corner.
ImageFLOW also supports scan-to-file and scan-to-print operations for more than 550 printers. Printing is organized around a RIP system that lets users create sets and manipulate the print queue. Another nice feature is the ability to integrate prints from other software packages into the ImageFLOW printing queue, so the scanner can be a comprehensive company-wide ripping, queue and printing system.
ImageFLOW is one of the best scanner software applications I've seen, and it's very easy to learn and use. It supports multipage TIFF and PDF, so it's well-suited for archiving file formats. The ImageFLOW version I tested didn't support adaptive thresholding; however, it's expected in future releases.
I measured the vertical and horizontal accuracy as 0.20% and 0.11%, respectively. These measurements are among the best of the reviewed scanners. The line pairs per millimeter test came in at 4.7, which falls in the middle range of the tested scanners. The average time for an E-size black-and-white scan at 200-, 300- and 400dpi was 33 seconds per scan. This makes the Gx42 the slowest in the Cadalyst test. Paradigm Imaging plans future firmware upgrades that will double the scanning speed.
The ImagePRO Gx42 lets users scan, preview, print and copy images. It can even integrate prints from other software packages into the printing queue, so the scanner can be a com-prehensive company-wide ripping, queue and printing system.
Henrik Vestermark is an independent consultant for the Internet-based company The Other Solutions. His expertise includes all aspects of the wide-format and large-format digital capture market. Send e-mail to email@example.com.
About the Author: Henrik Vestermark
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