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Journal of Forensic Identification67 (3), 2017 \ 341

Received November 16, 2016; accepted January 24, 2017

Technical Note

Using Bluestar Forensic to Detect Latent Bloodstains under Coats of Paint

Maria Pettolina Jennifer Rainey Reanna SanchezParker Police Department Parker, Colorado

Abstract: The purpose of this experiment was to determine whether Bluestar Forensic was capable of detecting latent bloodstains under multiple coats of paint. In order to test this, three different blood-stain patterns (handprint transfer, drip, and hair swipe) were applied to three types of substrates (brick, f lakeboard, and dry wall). After each of the bloodstains had been applied to the substrates, the stains were systematically painted over multiple times with three separate colors and types of paint. After each coat of paint was applied and allowed to dry, Bluestar Forensic was then sprayed over the test areas to see whether a reaction occurred with the concealed bloodstain. Reactions were visualized, recorded, and photographed. The f indings of this study show that Bluestar Forensic was able to detect bloodstains through at least three to four layers of paint in most circumstances. However, results did vary and were dependent upon the type and color of paint used as well as the bloodstain pattern applied.

IntroductionBloodstains are often found in various places at crime scenes,

from f loors and bathtubs to walls and ceilings. Luminol is a popular blood-detecting chemical reagent that is frequently used

Journal of Forensic Identification342 / 67 (3), 2017

at crime scenes to detect latent bloodstains. However, Bluestar Forensic is a more advanced reagent that is gaining popularity among crime scene investigators. Bluestar is based on luminol’s chemical formula; so, like luminol, it reacts with the hemoglobin in the blood and produces a chemiluminescence that is visible to the naked eye. Though it is similar to luminol, Bluestar is easier to prepare and use in the field because it comes in preformulated tablets and has a stronger, longer-lasting luminescence that does not require full darkness. Also of importance is that it does not destroy DNA. Therefore, it is safe to use on suspected blood-stains that may also be swabbed for subsequent DNA testing [1].

Previous research has demonstrated the ability to detect bloodstains under multiple layers of paint using numerous methods. However, the majority of these experiments have focused on the detection of bloodstains under painted surfaces using var ious alternate light sources (ALSs) and infrared photography. For example, Adair [2] used ALSs to detect blood under paint. In his experiment, the SPEX units provided the best results when used with a deep yellow filter. Other authors have had good success with different Polilight ALS models [2]. There are only a few studies that have tested the ability of chemical reagents to detect bloodstains that have been concealed by paint. One study by Howard and Nessan [3] compared f ive separate techniques, including Bluestar, for the detection of bloodstains under multiple layers of paint. Additionally, a study by Bily and Maldonado [4] showed that luminol can detect bloodstains concealed by up to eight layers of white paint. Despite this previ-ous research, there are still unanswered questions regarding the use of Bluestar Forensic itself. Therefore, rather than comparing alternate techniques or the effectiveness of luminol, the purpose of our research was to demonstrate the ability of Bluestar to detect bloodstains under multiple layers of paint given certain variables. Specifically, we hoped to establish whether variables such as type and color of paint, substrate, and bloodstain pattern made a difference in the reagent’s ability to detect bloodstains covered by paint.

Materials and MethodsThe experiment was completed following procedures in

accordance with the Journal of Forensic Identif ication’s Human Subject Protection Policy [5], which supports the International Association of Identification’s Code of Ethics and Standards of Professional Conduct. Three different substrates (brick, f lake-


board, and drywall) and three different colors and types of paint were used (Table 1). Paint 1 was a Clark and Kensington premium interior satin enamel paint, 100% acrylic latex enamel, with primer, and ceramic micro bead technology in a dark purple color called “Wild Grapes” (Ace Hardware Corporation, Oak Brook, IL). Paint 2 was a Behr Marquee interior 100% acrylic paint with an eggshell base, primer, and stain block-ing power in a blue-green color called “Aqua Rapids” (Behr Process Corporation, Santa Ana, CA). Paint 3 was a Valspar interior 100% acrylic enamel paint with an eggshell base, but no primer, considered “Eggshell” in color (The Valspar Corporation, Minneapolis, MN). The following bloodstain patterns were used: a handprint transfer pattern (designated as Stain 1), a drip pattern (designated as Stain 2), and a hair swipe pattern (designated as Stain 3). All bloodstains were made using defibrinated sheep’s blood purchased from Colorado Serum Company (Lot No. 4116). The handprint transfer patterns were created by submerging a hand into the blood and placing it on the designated test area of each substrate. Each handprint transfer pattern utilized approxi-mately 2 to 3 mL of blood and measured approximately 17 cm in length by 12 cm in width. The drip patterns were made by using an eyelet dropper and dripping two drops, at a 90-degree angle, onto the designated test area of each substrate. Each drop utilized approximately 0.25 mL of blood and measured approxi-mately 4 to 5 mm in diameter. The hair swipe patterns were created by soaking a mannequin’s hair in the blood and then swiping it across the designated test area of each substrate. The swipe patterns utilized approximately 5 to 6 mL of blood and were made across an area of 20 cm in length by 12 cm in width.

Paint 1 Premium, interior, acrylic latex enamel paint, with primer, in dark purple

Paint 2 Interior, acrylic paint with primer and stain blocking power in blue/green

Paint 3 Interior, acrylic paint in eggshell

Stain 1 Handprint transfer pattern

Stain 2 Drip pattern

Stain 3 Hair swipe pattern

Table 1 Paints and stains used.


To set up the experimental design for the drywall and f lake-board, each first had to be sectioned off into individual testing areas. A permanent, black marker was used to draw grids along the surfaces of the drywall and f lakeboard. The f irst column of each grid was designated as the negative control column. In these testing areas, the substrate itself and each paint were tested with Bluestar to see whether there were false positive reactions with any of the paints or either substrate. The second column of each grid was designated as the Stain 1 column. The third column was designated the Stain 2 column. The fourth and final column was designated as the Stain 3 column. Along the first row of each grid, Paint 1 was used. Similarly, for the second row, Paint 2 was used, and for the third row, Paint 3 was used (Figures 1, 2).

In order to set up the experimental design for the bricks, 10 bricks were used. The bricks were subsequently numbered and each was assigned a bloodstain pattern and paint color with the exception of Brick #1, which was designated as the negative control brick. Brick #1 was sectioned off into three parts on one side (Figure 3). Each one of these sections was painted with one of the paints and later tested with Bluestar to be sure there were no false positive reactions with any of the paints on this substrate. The opposite side of Brick #1 was used as the substrate negative control. Therefore, this side of the brick was directly sprayed with Bluestar to check for a false positive reaction with the substrate itself. The bloodstain pattern and paint color for Bricks # 2 to #10 were assigned numbers the same as with the drywall and f lakeboard layouts. Figure 4 is an example of how Bricks # 2 to # 10 were set up according to their number assign-ments.

When the grids on the drywall and f lakeboard were finished and the bricks were assigned their number, pattern, and paint, all testing areas were painted with the appropriate color of paint and allowed to dry for approximately 48 hours. Next, Bluestar Forensic was mixed according to package instructions and tested on all negative controls in low ambient light. No false positives for the paints were noted (Figure 5). Additionally, it was tested on the sheep’s blood as a positive control and resulted in a strong reaction (Figure 6).

After all of the controls were completed, the bloodstain patterns were applied to each of the designated test areas. All patterns were then allowed to dry for a couple of hours prior to the application of the f irst coat of paint. The f irst coat of paint was allowed to air dry for a few hours as well. When the paint was fully dry, each designated test area was individually


sprayed with Bluestar, and reactions were photographed and recorded on the basis of the strength of the reaction visualized. As per Bluestar instructions, all testing and photography was performed in low ambient light.

The reactions were visualized, ranked, and documented as 0, 1, 2, or 3, according to the strength of the reaction witnessed. The ranking system was as follows:

• A reaction ranked 0 was considered no visible reaction.• A reaction ranked 1 was considered a weak, but still visible

reaction.• A reaction ranked 2 was considered a good reaction with some

visible pattern detail.• A reaction ranked 3 was considered a strong reaction with

clearly visible pattern detail.

This process was repeated for the second, third, and fourth coats of paint. Drying times between the second, third, and fourth coats of paint ranged from 48 hours to 1 week.

Figure 1Drywall experimental design layout.

Figure 2 Flakeboard experimental design layout.


Figure 4 Example of brick experimental design layout.

Figure 3 Control brick.


(a) (b)Figure 5

Paint swatches for use as a negative control; (a) prior to testing; (b) treated with Bluestar.

(a) (b)Figure 6

Sheep’s blood: (a) prior to testing; (b) treated with Bluestar.


ResultsThe results of this study demonstrate that Bluestar Forensic

is capable of detecting bloodstains under multiple layers of paint (Table 2). However, factors such as paint color and type, as well as bloodstain pattern, do affect its ability to do so. Conversely, the substrate did not appear to make a significant difference in the results.

Table 2 Results of the study.

(Graphic provided courtesy of Alice Bendig, Wheeling, IL)

On the f lakeboard substrate, Bluestar was unable to detect two of the three bloodstain patterns after three coats of either Paint 1 or Paint 2. Though it was able to detect some of Stain 3 after four coats of both of these paints, the reactions were barely visible and short-lived. Therefore, these reactions were ranked a 1. Bluestar was better able to detect the bloodstains covered with Paint 3. Even after four layers of Paint 3, all three blood-stains were still visible, although to varying degrees. Stain 1 and Stain 2 patterns were barely detectable, so were ranked a 1, but Stain 3 was still visible with some pattern detail; therefore, it was ranked a 2. Figures 7a and 7b are examples of the results witnessed for Paint 1 and Stain 3 after one coat of paint (reaction ranked 3) versus four coats of paint, when the bloodstain was weak and barely visible (reaction ranked 1).


The results on the drywall substrate were similar to the f lake-board with only a couple of exceptions. It took four layers of Paint 1, rather than three, to completely cover two of the three bloodstain patterns tested. As before, Bluestar was still able to detect some of Stain 3 after four coats, though the reaction was barely visible and the pattern was not identifiable. This result was ranked a 1. Paint 2, however, was successful at covering all bloodstains after three coats. Like the f lakeboard substrate, Bluestar was able to detect all three bloodstains after four coats of Paint 3. Stain 1 and Stain 3 were visible with some pattern detail, so they were ranked a 2. Stain 2 was barely visible after four coats; therefore, it was ranked a 1. Figure 8 shows the result for Paint 2 and Stain 1 after one coat of paint (reaction ranked 3), whereas with three coats of paint, the bloodstain was no longer visible (reaction ranked 0).

The brick substrate results are consistent with most of the findings of the other two substrates. Bluestar Forensic was either unable or barely able to detect the bloodstains under three to four layers of paint. As with the other substrates, Paint 1 and Paint 2 were more successful at covering the bloodstains as compared to Paint 3. Figure 9 demonstrates the results of Paint 3 and Stain 2 after one coat of paint (reaction ranked 3), whereas four coats of paint, resulted in a weak bloodstain and was barely visible (reaction ranked 1).

(a) (b)Figure 7

Results of Bluestar after: (a) one coat of paint (Paint 1) on Stain 3 (reaction ranked a 3); (b) four coats of paint (Paint 1) on Stain 3

(reaction ranked a 1).


Figure 9 Results of Bluestar after one coat of paint (Paint 3) on Stain 2 (reaction

ranked a 3).

Figure 8 Results of Bluestar after one coat of paint (Paint 1) on Stain 3 (reaction

ranked a 3).


DiscussionThe results of our experiment showed that Bluestar Forensic

was capable of detecting bloodstains through three to four layers of paint, depending on the paint and the bloodstain pattern. However, its effectiveness at detecting the bloodstains decreased with each layer applied. It is interesting to note that the two variables that seemed to affect the results were the type and color of paint used and the bloodstain pattern applied. Although all three paints (acrylic) were interior, they did differ in color and composition. Paint 1 was a dark purple “premium” acrylic latex enamel paint with primer. Paint 2 was a blue-green paint that contained primer in addition to having stain blocking power. Conversely, Paint 3 was not only lighter in color, but was also a basic, interior acrylic paint without primer. Consequently, on the basis of the results of this study, Paint 1 and Paint 2 were better at concealing the underlying bloodstain patterns.

Regarding the bloodstain pattern used, the patterns that utilized the greatest volume of blood and covered the most surface area, especially Stain 3, were the ones that were most easily detected by Bluestar, regardless of the paint or substrate. Presumably, this may be because, with a greater volume of blood and a larger amount of surface area covered by the pattern, there was more potential for reactivity with the chemical reagent. Alternately, Stain 2 consisted of approximately 0.25 mL of blood per drop, with each drop only encompassing approxi-mately 4 to 5 mm worth of substrate. Therefore, it may not have allowed for as much opportunity for detection, given the greatly reduced volume and surface area involved.

This project could serve as a basis for future study. Other types and colors of paints could be tested. As was shown in the results of this experiment, paint type and color did affect the ability of Bluestar to detect the blood through multiple layers. In addition, although a couple of the paints tested did include primer (Paint 1 and Paint 2) and one (Paint 2) had stain blocking power, it would be valid to test paint primers on their own. For example, KILZ Max primer is an interior, water-based primer that is advertised to help block severe stains and odors [6]. Therefore, Bluestar’s ability to detect bloodstains covered by KILZ Max primer, as well as other KILZ products, would be well worth investigating.

Additional bloodstain patterns could also be examined. As discussed, the volume of blood that was utilized and the surface area of substrate encompassed by the three types of bloodstains


that were tested had an impact on our results. These variables could be further analyzed through the use of differing bloodstain patterns. Though substrate type did not seem to significantly affect our results, this could be explored further as well.

Finally, another area for further research could be to run a similar experiment incorporating the variable of bloodstains that were “cleaned” prior to being painted over. On the basis of the results of this experiment, it would seem that cleaning prior to painting would make the blood harder to detect through multiple layers of paint, but it could also add another difficulty with regards to false positives. Any agent used to clean the blood prior to painting, including water, would need to be tested as a negative control.

ConclusionBluestar Forensic is an effective chemical reagent for detecting

bloodstains through multiple layers of paint, though that ability decreases with each layer of paint applied. Additionally, the type and color of paint do seem to affect Bluestar’s ability to detect the blood. Specially formulated paints, such as those that are made to cover stains, successfully cover the bloodstains with only a few applications. Also of importance is the type of bloodstain pattern present. Bloodstains that are composed of a greater volume of blood and cover a larger surface area seem to have an increased potential for detection, regardless of color or type of paint used. Conversely, substrate type did not seem to significantly affect how well Bluestar detected the concealed bloodstain. Despite these variables and potential limitations, Bluestar Forensic has the ability to detect bloodstains covered by paint and should be considered at any crime scene in which the investigator suspects that the perpetrator may have attempted to do so.

AcknowledgmentThe authors would like to thank Faye Borquez and Sandra

Fisher of the Aurora Police Department in Aurora, Colorado, for their input and time on this research project.

For further information, please contact:Maria C. PettolinaParker Police Department18600 E. Lincoln Meadows ParkwayParker, CO [email protected]


References1. Bluestar Forensic. Bluestar Forensic Latent Blood Reagent.

2004. http://www.bluestar-forensic.com/gb/bluestar.php (accessed Septermber 2015).

2. Adair, T. W. Experimental Detection of Blood under Painted Surfaces. I.A.B.P.A. News, March 2006, pp 12–19.

3. Howard, M. C.; Nessan, M. Detecting Bloodstains under Multiple Layers of Paint. J. For. Ident. 2010, 60 (6), 682–717.

4. Bily, C.; Maldonado, H. The Application of Luminol to Bloodstains Concealed by Multiple Layers of Paint. J. For. Ident. 2006, 56 (6), 896–905.

5. Journal of Forensic Identif ication Research Subjects P ro te c t i o n Po l i c y. I n t e r n a t ion a l A s so c ia t ion fo r Identif ication, Hollywood, FL, 2014. www.theiai.org/jf i/HumanSubjectsProtectionPolicy2014.pdf (accessed January 2017 ).

6. Masterchem Industries LLC. Kilz Products. 2016. http://www.kilz.com/products/primer/kilz-max?&gclid=CKDg3ePil9ECFYKVfgodalkO2w (accessed December 2016 ).

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